Non root

[tonyskapunk]

Fix #35

[tonyskapunk@gnu:~]$ python kthresher.py --purge --verbose                                                                          
INFO: Attempting to read /etc/kthresher.conf.
INFO: Options found: ['include'].
INFO: Valid setting found "include"
INFO:   include = /etc/kthresher.d/*.conf
INFO: Attempting to read /etc/kthresher.d/kthresher.conf.
INFO: Options found: ['purge', 'keep', 'headers', 'verbose'].
INFO: Valid setting found "purge"
INFO:   purge = True
INFO: Valid setting found "keep"
INFO:   keep = 0
INFO: Valid setting found "headers"
INFO:   headers = True
INFO: Valid setting found "verbose"
INFO:   verbose = True
INFO: Options: {'verbose': True, 'dry_run': False, 'keep': 0, 'purge': True, 'headers': True, 'include': '/etc/kthresher.d/*.conf'}
INFO: Running kernel is linux-image-4.9.0-2-amd64 v[4.9.13-1]
INFO: Attempting to keep 0 kernel package(s)
INFO: Found 1 kernel image(s) installed and available for autoremoval
INFO: Pre-sorting: ['3.16.7-ckt25-2']
INFO: Post-sorting: ['3.16.7-ckt25-2']
INFO:   Purging packages from version: 3.16.7-ckt25-2
INFO:           Purging: linux-image-3.16.0-4-amd64
ERROR: Failed to lock /var/cache/apt/archives/lock, are you root?