Generated spec file to be ignored is named git.spec and not git-core.spec

Signed-off-by: NJakub Narebski <jnareb@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

.gitignore

@@ -156,7 +156,7 @@ common-cmds.h
 *.tar.gz
 *.dsc
 *.deb
-git-core.spec
+git.spec
 *.exe
 *.[ao]
 *.py[co]