message catalogs: fix comment lines, also remove linux hack in merge.c

According to the spec, blank lines in message catalogs or lines
beginning with '$ ' are valid comments.

However, there were many cases where lines in the message catalogs
contained just a single '$', without the required space after it.

Under linux, this caused 126766 error lines (in my builds) of the
form:

... unknown directive `': line ignored

This also causes gencat to exit with a non-0 exit code.  Even though
gencat says it ignores the line, it really doesn't.

An early porting change to programs/localized/util/merge.c was made to
ignore this return value on linux.  This hack has now been removed.

Build logs are a lot smaller and cleaner now.

cde/programs/localized/ko_KR.dt-eucKR/config/dtfile.config.tmsg

@@ -25,7 +25,7 @@ $ *                         \t                  horizontal tab
 $ *                         \ (at end of line)  continue on same line
 $ *
 $ *****************************************************************************
-$
+$ 
 1 AFS ACL 변경...
 2 검사 대화 표시...
 3 경고: 이것은 Andrew File System (AFS) 오브젝트입니다.\\n사용 권한은 AFS 사용 제어 목록(ACL)에 의해 제한될 수 있습니다.