mount3: Do not return error when mount list is empty
mount3: Do not return error when mount list is empty

An exports list can be empty when no subvolumes have come up.
No point returning error and confusing the user.

Signed-off-by: Shehjar Tikoo <shehjart@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 2345 (Taking distribute brick down returns 10006 error on mount command)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=2345

Kaushikbv/Gluster,Kaushikbv/Gluster,Kaushikbv/Gluster