If we verify the failure is due to buildbot, bump Fix Version to 2.5.2.

Linux RHEL 64-bit Build #1377

Edit: http://buildbot.mongodb.org/builders/Linux%20RHEL%2064-bit/builds/1377/steps/test_9/logs/stdio (was http://buildbot.mongodb.org/builders/Linux%20RHEL%2064-bit/builds/1377/steps/test_8/logs/stdio)

What's peculiar here is, apparently, there were no test failures, only buildlogger URLErrors. stdio (1377/steps/test_8/logs/stdio) ends with:

708 tests succeeded
scons: done building targets.
program finished with exit code 0
elapsedTime=2936.038493

Yet Buildbot still considered this build as failed.