fix shell syntax error in template

An if clause must not be empty; add a "colon" command.

Signed-off-by: Thorsten Glaser <t.glaser@tarent.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'maint-1.8.2' into maint-1.8.3

* maint-1.8.2:
  fix shell syntax error in template