cli: command parse validation
cli: command parse validation

Signed-off-by: Pranith Kumar K <pranithk@gluster.com>
Signed-off-by: Vijay Bellur <vijay@dev.gluster.com>

BUG: 1431 (cli: check if arguments exist before the accessing them)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=1431

Kaushikbv/Gluster,Kaushikbv/Gluster,Kaushikbv/Gluster