Fix memory leak with multiple %lang-s in one line

We permit two equivalent forms of specifying a list of languages per
file:

  %lang(xx,yy,zz) /path/to/file
  %lang(xx) %lang(yy) %lang(zz) /path/to/file

The leak was when parsing the second form.

Found by Coverity.

build/files.c

@@ -777,6 +777,8 @@ static rpmRC parseForLang(char * buf, FileEntry cur)
 
 	if (*pe == ',') pe++;	/* skip , if present */
     }
+
+    q = _free(q);
   }
 
     rc = RPMRC_OK;