expression parser: Fix (theoretical) memory leak.

Fix a memory leak that is very unlikely to actually happen.  If a malloc()
succeeded, but the following strdup() failed, the memory from the original
malloc() would be leaked.


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@360356 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/ast_expr2.y

@@ -532,6 +532,9 @@ make_str (const char *s)
 
 	vp = (struct val *) malloc (sizeof (*vp));
 	if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
+		if (vp) {
+			free(vp);
+		}
 		ast_log(LOG_WARNING,"malloc() failed\n");
 		return(NULL);
 	}