failed imports do not clean up correctly

[tfoote]

This is refiling from ros-infrastructure/ros_buildfarm#304.

Failures like this don't clean up the import directly leading to buildup. And potentially conflicts like ros-infrastructure/ros_buildfarm#305

After catching the error before cleaning up it should clear the directory on the server.

# BEGIN SECTION: import debian package
00:00:00.638 + export PYTHONPATH=/home/jenkins-slave/workspace/Irel_import-package/reprepro-updater/src:
00:00:00.638 + python -u /home/jenkins-slave/workspace/Irel_import-package/reprepro-updater/scripts/include_folder.py --folder /var/repos/ubuntu/building/queue/trusty/Isrc_uT__baxtereus__ubuntu_trusty__source__14 --package ros-indigo-baxtereus --delete-folder --commit --invalidate
00:00:00.682 running command ['reprepro', '-b', '/var/repos/ubuntu/building', '-T', 'dsc', '-V', 'removefilter', u'trusty', 'Package (== ros-indigo-baxtereus )']
00:00:00.936 removing 'ros-indigo-baxtereus' from 'trusty|main|source'...
00:00:00.936 Exporting indices...
00:00:00.936 Successfully created '/var/repos/ubuntu/building/dists/trusty/Release.gpg.new'
00:00:00.936 Successfully created '/var/repos/ubuntu/building/dists/trusty/InRelease.new'
00:00:00.936 Deleting files no longer referenced...
00:00:00.936 deleting and forgetting pool/main/r/ros-indigo-baxtereus/ros-indigo-baxtereus_1.0.6-1trusty.debian.tar.gz
00:00:00.936 deleting and forgetting pool/main/r/ros-indigo-baxtereus/ros-indigo-baxtereus_1.0.6-1trusty.dsc
00:00:00.936 running ['reprepro', '-v', '-b', '/var/repos/ubuntu/building', 'deleteunreferenced']
00:00:00.936 running command ['reprepro', '-v', '-b', '/var/repos/ubuntu/building', 'deleteunreferenced']
00:00:01.101 Importing package: ros-indigo-baxtereus:1.0.6-2trusty:trusty:source
00:00:01.101 running command ['reprepro', '-v', '-b', '/var/repos/ubuntu/building', '-S', 'misc', 'include', u'trusty', '/var/repos/ubuntu/building/queue/trusty/Isrc_uT__baxtereus__ubuntu_trusty__source__14/ros-indigo-baxtereus_1.0.6-2trusty_source.changes']
00:00:01.108 File "pool/main/r/ros-indigo-baxtereus/ros-indigo-baxtereus_1.0.6.orig.tar.gz" is already registered with different checksums!
00:00:01.108 md5 expected: d755f2f3587e1edbf30aa216aab750d8, got: 44dde8c20325543eb7c4274c0c73908e
00:00:01.108 sha1 expected: 45d5deba6671156f31cac2c2d24e445503d240b9, got: ff669b80c1636ea1fce6a82a6cf1fd06ee850f4f
00:00:01.108 sha256 expected: 7451ae3d764852788caad447170defe4d7cb2ef1f9083195f5367e98894c35d4, got: 49a747edafea90521eaaf7ca8182e5b1f71a51827a7568bfafea7d77ec389e57
00:00:01.108 size expected: 2258193, got: 2258187
00:00:01.108 There have been errors!
00:00:01.108 Execution of [['reprepro', '-v', '-b', '/var/repos/ubuntu/building', '-S', 'misc', 'include', u'trusty', '/var/repos/ubuntu/building/queue/trusty/Isrc_uT__baxtereus__ubuntu_trusty__source__14/ros-indigo-baxtereus_1.0.6-2trusty_source.changes']] Failed: Command '['reprepro', '-v', '-b', '/var/repos/ubuntu/building', '-S', 'misc', 'include', u'trusty', '/var/repos/ubuntu/building/queue/trusty/Isrc_uT__baxtereus__ubuntu_trusty__source__14/ros-indigo-baxtereus_1.0.6-2trusty_source.changes']' returned non-zero exit status 254
00:00:01.116 Build step 'Execute shell' marked build as failure
00:00:01.125 [description-setter] Could not determine description.
00:00:01.144 Email was triggered for: Failure - Any
00:00:01.144 Sending email for trigger: Failure - Any
00:00:01.148 Sending email to: ros-buildfarm-indigo@googlegroups.com tfoote+buildfarm@osrfoundation.org
00:00:01.203 Finished: FAILURE