Updated post-reviews.py to use the correct apache git mirror.

Review: https://reviews.apache.org/r/11091
Fixed the MonitorTest by setting the timestamp of the
ResourceStatistics.

Review: https://reviews.apache.org/r/10715
Simplify os::hostname() in libstout.
Run Hadoop tutorial binaries from within build dir.
Include pre/post-package hook scripts in Hadoop tutorial.
Allow ending Hadoop tutorial early.

Allow someone to end tutorial after building/packaging complete.  You
can also skip the test part by exporting SKIP_TESTS (i.e., 'make hadoop
SKIP_TESTS=1').
Use XZ (LZMA) for package on Linuxes.
Build fix for HadoopPipes.cc with GCC 4.7.
Check for Python.h in configure script.
Use more portable paths for tutorial test.
Improve MesosScheduler for Hadoop.

We'll try to allocate map/reduce slots in such a way that we ensure we
utilize the entire cluster effectively.  We'll use up to the maximum
desired number of map/reduce slots, starting from a minimum of 1 map or
1 reduce slot.
Don't prematurely kill TaskTrackers.

We assign the JobID to the internal Mesos tracker (for the TaskTracker)
rather than the TaskID.

In the case where a TaskTracker has only map tasks assigned to it and
they have all completed, we mustn't terminate the tracker until the
entire job has finished, including the map tasks.
Hadoop tutorial version bump (CDH4.2.0 -> 4.2.1).
Shuffle offers before sending to frameworks.

This helps ensure fair allocation of resources.
Slave feature: maximum system load.

When the load exceeds a specified value, don't accept tasks.  Some nodes
may become unstable under excessive load (i.e., heavy disk I/O), and
this helps prevent the assigning of further tasks to busy slaves.
Log executor output to syslog.
Kill tasks that never properly launch.

After trying to launch a task tracker, we'll wait up to 5 minutes before
giving up and killing the task.
Terminate executors that aren't needed.

If we launch an executor and then kill the task immediately after, make
sure we also terminate the executor when there are no other tasks.
Make sure you clean up the cgroups test.

Sometimes the cgroup test fails because the directory is already there.
This should ensure that it gets cleanup up in that case before we exit.
Turn down noise from ZooKeeper.