MAINTAINERS: Update InfiniBand subsystem maintainer

Since Roland stepped down, the community asked me to take his place, and
the nomination was followed by sufficient votes and no dissensions that
we can move forward with the change.

Signed-off-by: Doug Ledford <dledford@redhat.com>

MAINTAINERS

@@ -5042,13 +5042,13 @@ S:	Orphan
 F:	drivers/video/fbdev/imsttfb.c
 
 INFINIBAND SUBSYSTEM
-M:	Roland Dreier <roland@kernel.org>
+M:	Doug Ledford <dledford@redhat.com>
 M:	Sean Hefty <sean.hefty@intel.com>
 M:	Hal Rosenstock <hal.rosenstock@gmail.com>
 L:	linux-rdma@vger.kernel.org
 W:	http://www.openfabrics.org/
 Q:	http://patchwork.kernel.org/project/linux-rdma/list/
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband.git
+T:	git git://github.com/dledford/linux.git
 S:	Supported
 F:	Documentation/infiniband/
 F:	drivers/infiniband/