boot: Relax getSnapshotMergeStatus test.

The SNAPSHOTTED state is allowed to be NONE if the slot hasn't changed,
to avoid needing extra snapshot cancels in the bootloader.

Bug: 154449745
Test: vts
Change-Id: Ibcb9f18f535cdcb5aae7e2c9c01e03681dbfff13
Merged-In: Ibcb9f18f535cdcb5aae7e2c9c01e03681dbfff13
1 file changed