Fix update and check functionality

The return value of the check-function is tested properly in the
if-statements now.
Before we're comparing any references we're actually updating them first
with 'git remote update'

Signed-off-by: hjan <hoeppner.jan@xurv.org>
Merge https://github.com/hjan/vim-setup

Signed-off-by: hjan <hoeppner.jan@xurv.org>

Conflicts:
	install.sh