MT#61842 jdg-tap-tool-dispatcher: fix file-list handling with jdg-tap-merge-conflict

Noticed via:

| *** Skipping pep8 checks as tool pep8 isn't present ***
| mkdir -p reports/source/functions ; /usr/bin/jdg-tap-checkbashism source/functions/host-summary > reports/source/functions/host-summary_checkbashism.tap ; /usr/bin/jdg-tap-perlcritic source/functions/host-summary > reports/source/functions/host-summary_perlcritic.tap ; /usr/bin/jdg-tap-shellcheck source/functions/host-summary > reports/source/functions/host-summary_shellcheck.tap ;
| File source/functions/host-summary doesn't look like perl [Bourne-Again shell script, Unicode text, UTF-8 text executable]. Ignoring.
| Error: file {} could not be read.
| *** Getting rid of empty files ***

We're invoking jdg-tap-tool-dispatcher with the -f ... option,
to pass a certain list of files that should be checked.

Our generated execution script from jdg-tap-tool-dispatcher
looks like this:

  sed 's#^#source/#g' < /code/git.change | parallel -v -- \
    mkdir -p reports'/'{//} ';' \
  /usr/bin/jdg-tap-checkbashism '{}' '>' reports'/{}_checkbashism.tap' ';' \
  /usr/bin/jdg-tap-perlcritic '{}' '>' reports'/{}_perlcritic.tap' ';' \
  /usr/bin/jdg-tap-shellcheck '{}' '>' reports'/{}_shellcheck.tap' ';'
  /usr/bin/jdg-tap-merge-conflict '{}' '>' reports'/{}_mergecheck.tap' ';'

So we try to invoke /usr/bin/jdg-tap-merge-conflict outside of the
actual parallel run, as the trailing '\' in the shellcheck command line
is missing.

So /usr/bin/jdg-tap-merge-conflict is invoked with literally '{}', and
therefore complaining with:

  Error: file {} could not be read.

To avoid such a failure we need to end all jdp-* command lines with a
"\" to mark them for continuation in next line. Also let's add a
noop line to the end of the script to get valid code syntax. New
execution script now looks like this then:

  sed 's#^#source/#g' < /code/git.change | parallel -v -- \
    mkdir -p reports'/'{//} ';' \
  /usr/bin/jdg-tap-checkbashism '{}' '>' reports'/{}_checkbashism.tap' ';' \
  /usr/bin/jdg-tap-perlcritic '{}' '>' reports'/{}_perlcritic.tap' ';' \
  /usr/bin/jdg-tap-shellcheck '{}' '>' reports'/{}_shellcheck.tap' ';' \
  /usr/bin/jdg-tap-merge-conflict '{}' '>' reports'/{}_mergecheck.tap' ';' \
  # EOF

While at it, fix comment regarding generated script (we execute the
generated script, not generate the executed script :)), and also fix
a shellcheck issue reported for tap/jdg-tap-tool-dispatcher:

| In tap/jdg-tap-tool-dispatcher line 12:
| if [ $? -ne 0 ]; then
|      ^-- SC2181 (style): Check exit code directly with e.g. 'if ! mycmd;', not indirectly with $?.

Change-Id: I3c8a557712c1dad78c2404ea83e44ff281e077ac

tap/jdg-tap-tool-dispatcher

@@ -8,8 +8,7 @@ BASE_BIN=${BASE_BIN:-/usr/bin}
 CMDLINE_OPTS=disable-checkbashism,disable-pep8,disable-perlcritic,disable-shellcheck,disable-mergecheck
 CMDLINE_OPTS+=,file-list,help
 
-_opt_temp=$(getopt --name jdg-tap-tool-dispatcher -o -f+h --long $CMDLINE_OPTS -- "$@")
-if [ $? -ne 0 ]; then
+if ! _opt_temp=$(getopt --name jdg-tap-tool-dispatcher -o -f+h --long $CMDLINE_OPTS -- "$@") ; then
   echo "Try '$0 --help' for more information." >& 2
   exit 1
 fi
@@ -145,19 +144,22 @@ if ! [ -x "$(which shellcheck)" ] ; then
   echo "*** Skipping shellcheck checks as tool shellcheck isn't present ***"
 else
   if $_opt_shellcheck ; then
-    echo "${BASE_BIN}/jdg-tap-shellcheck '{}' '>' ${REPORTS_DIRECTORY}'/{}_shellcheck.tap' ';'" >> "${TMPFILE}"
+    echo "${BASE_BIN}/jdg-tap-shellcheck '{}' '>' ${REPORTS_DIRECTORY}'/{}_shellcheck.tap' ';' \\" >> "${TMPFILE}"
   else
     echo "*** Skipping shellcheck tests as requested via --disable-shellcheck ***"
   fi
 fi
 
 if $_opt_mergecheck ; then
-  echo "${BASE_BIN}/jdg-tap-merge-conflict '{}' '>' ${REPORTS_DIRECTORY}'/{}_mergecheck.tap' ';'" >> "${TMPFILE}"
+  echo "${BASE_BIN}/jdg-tap-merge-conflict '{}' '>' ${REPORTS_DIRECTORY}'/{}_mergecheck.tap' ';' \\" >> "${TMPFILE}"
 else
   echo "*** Skipping merge-conflict check tests as requested via --disable-mergecheck ***"
 fi
 
-# generate the executed script
+# generate noop to properly mark end of script
+echo "# EOF" >> "${TMPFILE}"
+
+# execute the generated script
 bash "${TMPFILE}"
 rm -f "${TMPFILE}"