Better error messages when mlockall fails

[rmuir]

For example on OS X:

[2015-05-30 11:22:14,095][WARN ][bootstrap                ] Unable to lock JVM Memory: error=78,reason=Function not implemented. This can result in part of the JVM being swapped out

On Linux:

[2015-05-30 11:23:53,596][WARN ][bootstrap                ] Unable to lock JVM Memory: error=12,reason=Cannot allocate memory. This can result in part of the JVM being swapped out
[2015-05-30 11:23:53,597][WARN ][bootstrap                ] Increase RLIMIT_MEMLOCK (ulimit). soft limit:65536, hard limit:65536

[rmuir]

I tried to improve messages more for the Linux case, to give some instructions on how to fix it:

[2015-05-30 12:22:53,792][WARN ][bootstrap                ] Unable to lock JVM Memory: error=12,reason=Cannot allocate memory. This can result in part of the JVM being swapped out.
[2015-05-30 12:22:53,792][WARN ][bootstrap                ] Increase RLIMIT_MEMLOCK, soft limit: 65536, hard limit: 65536
[2015-05-30 12:22:53,793][WARN ][bootstrap                ] These can be adjusted by modifying /etc/security/limits.conf, for example: 
    # allow user 'esuser' mlockall
    esuser soft memlock unlimited
    esuser hard memlock unlimited
[2015-05-30 12:22:53,793][WARN ][bootstrap                ] If you are logged in interactively, you will have to re-login for the new limits to take effect.

[s1monw]

cool stuff @rmuir this is a good improvement +1