Update submodules: installer (new commits)

installer:
    3af31a1 Shane Mc Cormack <shane@dmdirc.com>
            Update launcher for java 1.6 not 1.7 Improve code to detect java location on OS X.

            Gerrit: http://gerrit.dmdirc.com/2758

Change-Id: Ie93ee06b70960ce629f57df3e2ee31513a65d16b