When option mandatory is given, print warning messages instead of Error.
When option mandatory is given, print warning messages instead of Error.

Change the log level to Warning instead of Error.
Signed-off-by: Sachidananda Urs <sac@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 704 (GlusterFS starts despite error is logged in GlusterFS)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=704

Kaushikbv/Gluster,Kaushikbv/Gluster,Kaushikbv/Gluster