make chown of backend storage optional
don't check for the repository's master key
don't create the repository's whitelist
check for .cvmfswhitelist before import
adapt integration test 519
FIX: remove debug prints
FIX: unclear status print-out
FIX: improve error logging
adapt integration test case 550
Merge pull request #433 from reneme/fix-import

FIX: Import Creates Whitelist and Recursively chowns Backend Storage
add file descriptor detectors to cvmfs_server
add (verbose) warning for busy remount
add kill_cvmfs to cvmfs_suid_helper
add *_lazy_umount to cvmfs_suid_helper
allow `cvmfs_server abort` on busy mountpoint
allow `cvmfs_server publish` on busy mountpoint
allow `cvmfs_server rollback` on busy mountpoint
Merge pull request #434 from reneme/fix-remount_with_ro_fds

FIX: Transaction, Publish, Abort, Rollback with Open File Descriptors
additional sanity checks for cvmfs_suid_helper kill_cvmfs
cosmetics