rhel: Fix build failures because of libraries in /usr/lib.

Reported-by: Igor Sever <igor@xorops.com>
Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
ofproto-dpif: Get rid of mirror_mask_ffs() function.

There's no need for it because we have the equivalent (actually more
convenient) function raw_ctz(), which works with any integer type.

Signed-off-by: Ben Pfaff <blp@nicira.com>
CC: Alin Serdean <aserdean@cloudbasesolutions.com>
CC: Gurucharan Shetty <shettyg@nicira.com>