oop: Add an option to configure oop implementation

The final goal is to replace remoteFileHandler implementation
for outOfProcess with ioprocess.
We will do this in a series of steps
The first step is to add an option to manually configure
which one of the two implementations is to be used:
rfh or ioproc.

Change-Id: Ibd756afd43d23631dc7ed4bac64bec9a81b358b4
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1083771
Signed-off-by: Yeela Kaplan <ykaplan@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/26576
Reviewed-by: Yaniv Bronhaim <ybronhei@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>