BUG/MINOR: tools: make parseline report the required space for the trailing 0

The fix in commit 09a325a4de ("BUG/MINOR: tools: always terminate empty
lines") is insufficient. While it properly addresses the lack of trailing
zero, it doesn't account for it in the returned outlen that is used to
allocate a larger line. This happens at boot if the very first line of
the test file is exactly a sharp with nothing else. In this case it will
return a length 0 and the caller (parse_cfg()) will try to re-allocate an
entry of size zero and will fail, bailing out a lack of memory. This time
it should really be OK.

It doesn't need to be backported, unless the patch above would be.

src/tools.c

@@ -6504,13 +6504,13 @@ uint32_t parse_line(char *in, char *out, size_t *outlen, char **args, int *nbarg
 		goto leave;
 	}
  leave:
-	*nbargs = arg;
-	*outlen = outpos;
-
 	/* make sure empty lines are terminated */
 	if (!arg)
 		EMIT_CHAR(0);
 
+	*nbargs = arg;
+	*outlen = outpos;
+
 	/* empty all trailing args by making them point to the trailing zero,
 	 * at least the last one in any case.
 	 */