gitignore: unignore *.patch

This partially reverts:

 commit 082369e6
 Author: liguang <lig.fnst@cn.fujitsu.com>
 Date:   Fri Mar 22 16:44:13 2013 +0800

    gitignore: ignore more files

I'm not sure how this went in.  The thing is that
ignoring *.patch, in my opinion, is just wrong.
Especially for downstreams who apply patches for
real.
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

.gitignore

@@ -82,7 +82,6 @@ fsdev/virtfs-proxy-helper.pod
 *.swp
 *.orig
 .pc
-*.patch
 *.gcda
 *.gcno
 patches