Use absolute path references in the pants bootstrap script.

commit bc3d021389edf69a8db3135a2e9eafe3a2b20055
Author: John Sirois <jsirois@twitter.com>
Date:   Wed Apr 30 17:15:26 2014 -0600

    Use absolute path references in the pants bootstrap script.

    This allows pants to be run from sources in other repos.

 pants | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Testing Done:
I could use some help from Eric.

I concocted this local test though to confirm this works:

In my fork - this branch:
$ git diff
diff --git a/src/python/pants/bin/pants_exe.py b/src/python/pants/bin/pants_exe.py
index 70ade97..b10b832 100644
--- a/src/python/pants/bin/pants_exe.py
+++ b/src/python/pants/bin/pants_exe.py
@@ -165,6 +165,7 @@ def _run():
       NailgunTask.killall(None)

 def main():
+  print('>>> Customized locally in %s, running in %s' % (__file__, os.path.realpath(os.getcwd())))
   try:
     _run()
   except KeyboardInterrupt:

Then in pantsbuild/pants master:
$ PANTS_DEV=1 ~/dev-jsirois-pants/pants goal list | head
*** Running pants in dev mode from /home/jsirois/dev-jsirois-pants/src/python/pants/bin/pants_exe.py ***
>>> Customized locally in /home/jsirois/dev-jsirois-pants/src/python/pants/bin/pants_exe.py, running in /home/jsirois/dev/3rdparty/pantsbuild-pants
3rdparty/BUILD:antlr2
3rdparty/BUILD:antlr3
3rdparty/BUILD:antlr-3.4
3rdparty/BUILD:antlr4
3rdparty/BUILD:checkstyle
3rdparty/BUILD:commons-lang
3rdparty/BUILD:finagle-core
3rdparty/BUILD:finagle-thrift
3rdparty/BUILD:guava

Bugs closed: 94

Reviewed at https://rbcommons.com/s/twitter/r/302/
Issue 90: Add Add authentication files to pants bin target
Add tests for netrc

commit a0fce480bdc12343982e652fcd820f7f0c3a8141
Author: Tejal Desai <tdesai@twitter.com>
Date:   Wed Apr 30 20:27:35 2014 -0700

    Fix typo

commit 1b9f27304b06d846935bb18c297238b24e318f2d
Author: Tejal Desai <tdesai@twitter.com>
Date:   Wed Apr 30 11:53:19 2014 -0700

    Style check

commit af6fd235938ada3ba87eb96979945894ecda797d
Author: Tejal Desai <tdesai@twitter.com>
Date:   Wed Apr 30 11:51:53 2014 -0700

    Added style check

commit d5e59f42a06bbdc21e6656bd84eece642e91494b
Author: Tejal Desai <tdesai@twitter.com>
Date:   Wed Apr 30 00:49:46 2014 -0700

    Added tests and code review comments

commit 7616a0bd97b984d442e2acb697c6d50ac48e410e
Author: Tejal Desai <tdesai@twitter.com>
Date:   Tue Apr 29 13:40:08 2014 -0700

    Add authentication files to pants bin target
Hacky fix for issue with inner classes in .proto files with 'java_mulitple_files' enabled

Testing Done:
Updated test_cache_manager.py. Also fixes the issue with inner object definitions being expected to generate .java files from protoc in our repo.

Reviewed at: https://rbcommons.com/s/twitter/r/303/