Fix wipe command when using sideload in recovery

Add support for the wipe command when using sideload within the
recovery. All the support for this command is in place, only the
execution of the actual wipe command itself was missing.

Change-Id: Ia9cdfc912bfb9f558fa89b9f0ed54e843ede41f2
Signed-off-by: Christian Poetzsch <christian.potzsch@imgtec.com>