Allow simple_layout to support custom drivers

Instead of assuming a gerrit driver, allow the decorator caller to
define which driver to use for the source. Defaults to current behavior
of just gerrit.

Change-Id: Idc2b18fe08ee423abaf09a9f1c565ec021b0553a
Signed-off-by: Jesse Keating <omgjlk@us.ibm.com>
1 file changed