Use apt git package instead of git-core.

The git-core package is deprecated in favor of the git package. Use the
git package instead.

Change-Id: Ib136e34c7a0d4f87b02e32996420b3f507ca0bf4

files/apts/general

@@ -5,7 +5,7 @@ screen
 unzip
 wget
 psmisc
-git-core
+git
 lsof # useful when debugging
 openssh-server
 vim-nox