Fix additional memory leak in process_mapfile

Additional Coverity detected memory leak fix.

Submitted by:	bret_ketchum@dell.com
Reported by:	Coverity
Reviewed by:	cem, emaste
MFC after:	2 weeks
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D26462

lib/libpmc/pmu-events/jevents.c

@@ -821,6 +821,8 @@ process_mapfile(FILE *outfp, char *fpath)
 			/* TODO Deal with lines longer than 16K */
 			pr_info("%s: Mapfile %s: line %d too long, aborting\n",
 					prog, fpath, line_num);
+			free(line);
+			fclose(mapfp);
 			return -1;
 		}
 		line[strlen(line)-1] = '\0';