Change NameNode to start with: -XX:PermSize=128m -XX:MaxPermSize=256m by default

PROBLEM: We have seen full GCs in multiple customer environments caused due to the current PermSize for the namenode being too low.

GC entry that shows the issue:
2014-06-27T08:37:07.576+0000: 5030.881: [Full GC 5030.882: CMS: 29444717K->18807183K(80740352K), 135.6197500 secs 29685838K->18807183K(83571520K), 22577K->22479K(22784K)],+135.6199670+secs">CMS Perm : 22577K->22479K(22784K)] , 135.6199670 secs Times: user=134.95 sys=0.61, real=135.62 secs

The settings which passes are:
XX:PermSize=128m -XX:MaxPermSize=256m.