sip_to_pjsip: Make multiline comment parsing consistent with Asterisk

In Asterisk configuration, a multiline comment starts with ;-- as long as it is
not followed by another dash (i.e. ;--- is not a multiline comment).

ASTERISK-28323 #close

Change-Id: I32dc38e0fac01d3c0805d27d35d2365a7c37ca72

contrib/scripts/sip_to_pjsip/astconfigparser.py

@@ -180,7 +180,7 @@ def remove_comment(line, is_comment):
         return "", True
 
     part = line.partition(COMMENT_START)
-    if part[1]:
+    if part[1] and not part[2].startswith('-'):
         # found multi-line comment start check string before
         # it to make sure there wasn't an eol comment in it
         has_comment = part[0].partition(COMMENT)