xlator.c/option-validation: change the log level to warning when given value is out of range.
xlator.c/option-validation: change the log level to warning when given value is out of range.

Signed-off-by: Raghavendra G <raghavendra@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 1214 (When cache-size is given out of range, error is logged but GlusterFS starts)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=1214

Kaushikbv/Gluster,Kaushikbv/Gluster,Kaushikbv/Gluster