libglusterfsclient: Generalize [RW] checks on dirs
libglusterfsclient: Generalize [RW] checks on dirs

This patch moves the read-write permission check on directory
inode into libgf_client_opendir, so that when I am next adding support
for the opendir syscall, I dont have to perform similar checks again,
outside this function.

Signed-off-by: Anand V. Avati <6a1810c170bd423868ce2e225ecea39d80cade0f@amp.gluster.com>

Kaushikbv/Gluster,Kaushikbv/Gluster,Kaushikbv/Gluster