git.spec: Workaround localized messages not put in any RPM

git.spec: Workaround localized messages not put in any RPM

Currently building git RPM from tarball results in the following
error:

  RPM build errors:
     Installed (but unpackaged) file(s) found:
     /usr/share/locale/is/LC_MESSAGES/git.mo

This is caused by the fact that localized messages do not have their
place in some RPM package.  Let's postpone decision where they should
be put (be it git-i18n-Icelandic, or git-i18n, or git package itself)
for later by removing locale files at the end of install phase.

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