Do not allow the overwriting of the RECREATE_TEST_DEV variable. When
this variable is enabled, common/rc -> common/config will reset it
to false after the test device recreation process. This allows for
differentiation in mount options for SCRATCH and TEST.
Signed-off-by: Daniel Gomez <da.gomez@samsung.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Zorro Lang <zlang@redhat.com> Signed-off-by: Zorro Lang <zlang@kernel.org>