Fix: Check repository dir apart from the base git dir

[meaksh]

This PR should fix an issue happening when certain repository has failed to be cloned.

On these cases, the following runs of gitarro would produce the next traceback during execution:

[manager-prs-susemanager-unittests] $ /bin/sh -xe /tmp/jenkins4518559196771098257.sh
+ /home/jenkins/bin/gitbot/gitarro.rb -r SUSE/spacewalk -c susemanager_unittests -d 'python backend pgsql unit test' -t /home/jenkins/jenkins-build/workspace/manager-prs-susemanager-unittests/gitbot_susemanager_unittests/spacewalk/susemanager-utils/testing/automation/susemanager-unittest.sh -u https://ci.suse.de/job/manager-prs-susemanager-unittests/4876/ -f susemanager/ -g /home/jenkins/jenkins-build/workspace/manager-prs-susemanager-unittests/gitbot_susemanager_unittests
/home/jenkins/bin/gitbot/lib/gitarro/git_op.rb:68:in `chdir': No such file or directory @ dir_chdir - spacewalk (Errno::ENOENT)
    from /home/jenkins/bin/gitbot/lib/gitarro/git_op.rb:68:in `rescue in goto_prj_dir'
    from /home/jenkins/bin/gitbot/lib/gitarro/git_op.rb:63:in `goto_prj_dir'
    from /home/jenkins/bin/gitbot/lib/gitarro/git_op.rb:28:in `merge_pr_totarget'
    from /home/jenkins/bin/gitbot/lib/gitarro/backend.rb:24:in `pr_test'
    from /home/jenkins/bin/gitbot/lib/gitarro/backend.rb:137:in `launch_test_and_setup_status'
    from /home/jenkins/bin/gitbot/lib/gitarro/backend.rb:121:in `reviewed_pr_test'
    from /home/jenkins/bin/gitbot/gitarro.rb:28:in `block in <main>'
    from /home/jenkins/bin/gitbot/gitarro.rb:12:in `each'
    from /home/jenkins/bin/gitbot/gitarro.rb:12:in `<main>'
...

The PR changes the behavior to actually check if the repository path exists. (not only the base git path).

/cc @MalloZup

[meaksh]

@MalloZup - I don't know why rubocop is not happy here while he's having a good time locally..

[juliogonzalez]

@meaksh, we can ignore rubocop this time. It's a problem from master. @MalloZup is working on it.

[MalloZup]

@meaksh thx LGTM for me. @juliogonzalez maybe we want to rebase the 2 commits? do we had a policiy for that ? :wolf:

[juliogonzalez]

Despite the command is rebase, in this context is best to say "squash".

And if my opinion counts... a PR should only have one commit so we can have the git history clean and easy to read :-)

[juliogonzalez]

BTW @meaksh, master is fixed now, so if you rebase the commits from master you will see travis running all the tests without any problem.

[meaksh]

@juliogonzalez - Rebased. Let's wait for rubocop 😄

[MalloZup]

@meaksh thx if rubocop is happy we can go with ti, ! thx for the handy fix!

[juliogonzalez]

@meaksh Could you squash the commits into a single one? :-)

[meaksh]

Ha! @juliogonzalez - Squashing ;-)

[juliogonzalez]

Thanks @meaksh! :-)

@MalloZup ready to merge as soon as the bot is happy about it.