Use unittest.addCleanup to simplify crypto_test.
Use unittest.addCleanup to simplify crypto_test.

Use unittest cleanups to remove temporary files instead of packing
everything into try-except-finally blocks.

atodorov/libblockdev,vpodzime/libblockdev,vpodzime/libblockdev,rhinstaller/libblockdev,rhinstaller/libblockdev,atodorov/libblockdev,vpodzime/libblockdev,atodorov/libblockdev,rhinstaller/libblockdev