Revert of mojo: Add a runloop utility in python

Revert of mojo: Add a runloop utility in python (patchset #3 id:40001 of https://codereview.chromium.org/552783004/)

Reason for revert:
This fails on the build bots.

======================================================================
ERROR: testRunLoop (runloop_unittest.RunLoopTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/mnt/data/b/build/slave/Linux_Tests/build/src/mojo/python/tests/runloop_unittest.py", line 24, in testRunLoop
    loop = system.RunLoop()
AttributeError: 'module' object has no attribute 'RunLoop'

http://build.chromium.org/p/chromium.linux/builders/Linux%20Tests/builds/13669/steps/mojo_python_bindings_tests/logs/stdio

Original issue's description:
> mojo: Add a runloop utility in python
>
> This is necessary to be able to use async operation on handles.
>
> R=sdefresne@chromium.org,cmasone@chromium.org
>
> Committed: https://crrev.com/830c88cca3c89dfabcbfc360ac7c035a020b8307
> Cr-Commit-Position: refs/heads/master@{#295267}

TBR=cmasone@chromium.org,sdefresne@chromium.org,qsr@chromium.org
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/0a1b918e47c7f2723a6542b62d69e7f271f731a3
Cr-Commit-Position: refs/heads/master@{#295280}

[battre, 2014-09-17 15:42:26]

Created Revert of mojo: Add a runloop utility in python

[commit-bot: I haz the power, 2014-09-17 15:43:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/575893004/1

[commit-bot: I haz the power, 2014-09-17 15:44:16]

Committed patchset #1 (id:1) as 0b92109faf863ac1c74529f1213ab1bd9c3ee32d

[commit-bot: I haz the power, 2014-09-17 15:45:05]

Patchset 1 (id:??) landed as
https://crrev.com/0a1b918e47c7f2723a6542b62d69e7f271f731a3
Cr-Commit-Position: refs/heads/master@{#295280}

[sdefresne, 2014-09-17 16:00:30]

lgtm