After upgrading to version 1.1.5 of the Git plug-in, our jobs on machines with Git 1.7.0 have started breaking since the Git plug-in issues "submodule" commands, which this version of Git apparently does not support.

It fails like this:
hudson.plugins.git.GitException: Error performing command: /ld/env/bin/git submodule init
Command "/ld/env/bin/git submodule init" returned status code 1: git: 'submodule' is not a git-command. See 'git --help'.

We don't even use submodules, so there's no reason for Jenkins to bother in the first place?