Remove unused imports.

cobbler/collection_manager.py:28: 'distro' imported but unused
cobbler/collection_manager.py:29: 'profile' imported but unused
cobbler/collection_manager.py:30: 'system' imported but unused
cobbler/collection_manager.py:31: 'repo' imported but unused
cobbler/collection_manager.py:32: 'image' imported but unused
cobbler/collection_manager.py:33: 'mgmtclass' imported but unused
cobbler/collection_manager.py:34: 'package' imported but unused
cobbler/collection_manager.py:35: 'file' imported but unused
PEP8: fix blank end of lines.

cobbler/action_buildiso.py:595:1: W391 blank line at end of file
cobbler/action_dlcontent.py:84:1: W391 blank line at end of file
cobbler/action_power.py:125:1: W391 blank line at end of file
cobbler/serializer.py:134:1: W391 blank line at end of file
cobbler/modules/serializer_couch.py:153:1: W391 blank line at end of file
cobbler/modules/serializer_file.py:198:1: W391 blank line at end of file
cobbler/modules/serializer_mongodb.py:161:1: W391 blank line at end of file
PEP8: indentation not multiple of four.

cobbler/api.py:138:26: E121 continuation line indentation is not a multiple of four
cobbler/api.py:139:26: E121 continuation line indentation is not a multiple of four
PEP8: cobbler/collection.py:347:45: E231 missing whitespace after ','
Merge pull request #1247 from jmaas/master

pep8 fixes