Description of problem:
Fix the following:
1. Add storage_merge_test.py to make file
2. Fix qemuimg_test.TestCommit
3. Fix test_merge_subchain
4. Handle errors when qemu chain isn't valid
5. Use volume.getBackingVolumePath when calling qemuimg rebase
6. Fix backing format when executing qemuimg rebase
Please add instructions for QE what to test here, if anything.
This BZ lists issues that were required in order to able to fix BZ 1410428 and BZ 1408977.
So, once BZ 1410428 and BZ 1408977 are verified, this one is verified as well.
Verified both BZ 1410428 and BZ 1408977 - moving to verified