unable to link to wheels when using relative paths

[lbragstad]

When passing relative paths to yaprt via the command line, like so:

yaprt --debug build-wheels \
       --report-file "repos/reports/release-report.json" \
       --storage-pool "repos/pools" \
       --link-dir "repos/releases/liberty" \
       --pip-bulk-operation \
       --build-output "/tmp/openstack-wheel-output" \
       --build-dir "/tmp/openstack-builder" \
       --build-requirements

it is possible to get an error like this:

Traceback (most recent call last):
  File "/home/jenkins/.pyenv/versions/default/bin/yaprt", line 11, in <module>
    sys.exit(main())
  File "/home/jenkins/.pyenv/versions/default/lib/python2.7/site-packages/yaprt/executable.py", line 197, in main
    runner(args, *function_args)
  File "/home/jenkins/.pyenv/versions/default/lib/python2.7/site-packages/yaprt/executable.py", line 160, in runner
    action(*function_args)
  File "/home/jenkins/.pyenv/versions/default/lib/python2.7/site-packages/yaprt/wheel_builder.py", line 100, in build_wheels
    force_iterate=True
  File "/home/jenkins/.pyenv/versions/default/lib/python2.7/site-packages/yaprt/wheel_builder.py", line 873, in build_wheels
    self._store_pool()
  File "/home/jenkins/.pyenv/versions/default/lib/python2.7/site-packages/yaprt/wheel_builder.py", line 780, in _store_pool
    wheel_name=os.path.basename(dst_wheel_file)
  File "/home/jenkins/.pyenv/versions/default/lib/python2.7/site-packages/yaprt/wheel_builder.py", line 809, in _create_link
    os.path.join(self.args['link_dir'], wheel_name)
OSError: [Errno 2] No such file or directory

It turns out if you pass relative paths to yaprt (--link-dir "repos/releases/liberty"), it could blow up with this error. The other thing I observed was that the symlinks from the --link-dir to the build pool might not exist, despite the pool being fully populated with the proper wheels.

The easiest work-around for this is to simply use absolute paths.

[cloudnull]

@lbragstad - This PR:#10 should fix the issues with relative paths when creating links..

[lbragstad]

Yep, I tested out PR #10 and it fixes the issue I was seeing.