make qa (pep8) fixes for cobbler/pxegen.py

cobbler/pxegen.py:74:25: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:76:25: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:79:25: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:81:25: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:85:21: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:87:21: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:91:17: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:95:17: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:99:17: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:103:21: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:106:21: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:110:17: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:114:17: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:182:28: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:387:21: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:388:21: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:393:21: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:394:21: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:403:25: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:532:13: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:602:37: E713 test for membership should be 'not in'
cobbler/pxegen.py:604:40: E713 test for membership should be 'not in'
cobbler/pxegen.py:606:40: E713 test for membership should be 'not in'
cobbler/pxegen.py:688:17: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:710:16: E713 test for membership should be 'not in'
cobbler/pxegen.py:740:13: E128 continuation line under-indented for visual indent
cobbler/pxegen.py:944:16: E714 test for object identity should be 'is not'