Make the config parser remove escaping backslashes

The config parser in Asterisk does not currently remove a backslash that is
used to escape a semicolon which would otherwise be interpreted as the start
of a comment.

The change here causes that backslash to be removed, but does not create a
real escape system in the config parser.  The biggest complication with a real
escape system would be breaking existing configs everywhere (parsing \\ as \
and breaking on escaped non-semicolon characters) even though it would be the
"right" way to do things.

(closes issue ASTERISK-17121)
Review: https://reviewboard.asterisk.org/r/1724/
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Merged revisions 354655 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 354656 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@354657 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/config.c

@@ -1538,7 +1538,9 @@ static struct ast_config *config_text_file_load(const char *database, const char
 				while ((comment_p = strchr(new_buf, COMMENT_META))) {
 					if ((comment_p > new_buf) && (*(comment_p - 1) == '\\')) {
 						/* Escaped semicolons aren't comments. */
-						new_buf = comment_p + 1;
+						new_buf = comment_p;
+						/* write over the \ and bring the null terminator with us */
+						memmove(comment_p - 1, comment_p, strlen(comment_p) + 1);
 					} else if (comment_p[1] == COMMENT_TAG && comment_p[2] == COMMENT_TAG && (comment_p[3] != '-')) {
 						/* Meta-Comment start detected ";--" */
 						if (comment < MAX_NESTED_COMMENTS) {