TT#29620 Update script/extract_i18n.sh to modern Sipwise shell policy

Also simplify the script

Change-Id: Ib2e0bbfeccd2160011c5e1a3afb26eee29704cd3

script/extract_i18n.sh

@@ -2,39 +2,35 @@
 
 set -e
 
-I18_DIRS="lib/NGCP/Panel/Role \
-lib/NGCP/Panel/Field \
-lib/NGCP/Panel/AuthenticationStore \
-lib/NGCP/Panel/Form \
-lib/NGCP/Panel/Render \
-lib/NGCP/Panel/Controller \
-lib/NGCP/Panel/Model \
-lib/NGCP/Panel/Utils \
-lib/NGCP/Panel/Widget \
-lib/NGCP/Panel/View \
-lib/NGCP/Panel/Cache \
-share/templates \
-share/layout"
+declare -a I18_DIRS=()
+I18_DIRS+=("lib/NGCP/Panel/Role")
+I18_DIRS+=("lib/NGCP/Panel/Field")
+I18_DIRS+=("lib/NGCP/Panel/AuthenticationStore")
+I18_DIRS+=("lib/NGCP/Panel/Form")
+I18_DIRS+=("lib/NGCP/Panel/Render")
+I18_DIRS+=("lib/NGCP/Panel/Controller")
+I18_DIRS+=("lib/NGCP/Panel/Model")
+I18_DIRS+=("lib/NGCP/Panel/Utils")
+I18_DIRS+=("lib/NGCP/Panel/Widget")
+I18_DIRS+=("lib/NGCP/Panel/View")
+I18_DIRS+=("lib/NGCP/Panel/Cache")
+I18_DIRS+=("share/templates")
+I18_DIRS+=("share/layout")
 
 POT="lib/NGCP/Panel/I18N/messages.pot"
 
-DIRS=""
-for d in ${I18_DIRS}; do
-	DIRS="$DIRS --directory $d"
-done
-
 echo; echo "Dumping DB and Form strings"; echo
 perl -I../sipwise-base/lib -I../ngcp-schema/lib -Ilib script/ngcp_panel_dump_db_strings.pl
 
-echo; echo "Creating $POT"; echo
+echo; echo "Creating ${POT}"; echo
 xgettext.pl \
-	--output=$POT \
-	$DIRS \
-	 -P perl=tt,pm
+  --output="${POT}" \
+  "${I18_DIRS[@]/#/--directory=}" \
+   -P perl=tt,pm
 
 while IFS= read -r -d '' po ; do
-	echo; echo "Merging $po"; echo
-	msgmerge --no-fuzzy-matching --add-location=file --update "$po" "$POT"
+  echo; echo "Merging ${po}"; echo
+  msgmerge --no-fuzzy-matching --add-location=file --update "${po}" "${POT}"
 done < <(find lib/NGCP/Panel/I18N -name "*.po" -print0)
 
 echo; echo "Removing line numbers"; echo