Fix #106 - Clicking 'Refresh' crashes Agit - by upgrade to ABS v4.4.0

Many thanks to @jwir3 for doing the git-bisect to find out that this was
introduced by upgrading to ABS 4.3.0 in 78dc1e1f.

The bug in ABS was covered in this issue:

https://github.com/JakeWharton/ActionBarSherlock/issues/902

...and fixed in this commit:

https://github.com/JakeWharton/ActionBarSherlock/commit/6ac7392d