Create static mesos library.

Review: https://reviews.apache.org/r/24252
Re-enabled HealthCheckTest.ConsecutiveFailures test.

The test originally was flaky because the time to process the number
of consecutive checks configured exceeds the task itself, so the task
finished but the number of expected task health check didn't match.

Review: https://reviews.apache.org/r/23772
Merge resourcesRecovered and resourcesUnused.

Review: https://reviews.apache.org/r/24331
Added executor metrics for slave.

Review: https://reviews.apache.org/r/24124
Changed socket closed while receiving to VLOG(2).
Fixed two flaky tests in AllocatorTest.

Review: https://reviews.apache.org/r/24418
MESOS-1170 Unbundle glog

Enable mesos to build against the system installed version of glog.

Review: https://reviews.apache.org/r/23453
Checked docker validation status code.

Review: https://reviews.apache.org/r/24419