patch 7.4.1596

Problem:    Memory leak. (Coverity)
Solution:   Free the pattern.

src/ex_cmds2.c

@@ -3404,6 +3404,7 @@ add_pack_plugin(char_u *fname, void *cookie)
 	    vim_free(cmd);
 	}
 #endif
+	vim_free(pat);
     }
 
 theend:

src/version.c

@@ -748,6 +748,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1596,
 /**/
     1595,
 /**/