This commit:
- removes std-srvs and rosgraph-msgs recipes, as their sources
now are located in the ros_comm_msgs repository.
- adds a recipe for the new roslz4 package, which rosbag-storage
depends on.
- removes the patch that has been merged upstream.

Besides updating ros-comm, this commit removes the second hash
values, that probably slipped-in during the last update.

Resolves:
  File "/usr/lib/python2.7/site-packages/rosservice/__init__.py", line 61, in <module>
    import rosmsg
ImportError: No module named rosmsg

The ros-comm 1.9.53 now also contains the new package rosbag-storage.

The ros-comm recipes are updated to 1.9.50 to be in line with
https://github.com/ros/rosdistro/blob/ef3a7449d7f7ef6e691a5724ef6c485e75cfd4af/hydro/release.yaml.

The ros-comm recipes are updated to 1.9.48 to be in line with
https://github.com/ros/rosdistro/blob/4551e7c32d1b34984410b79bc0ec36afe3d3d245/hydro/release.yaml.
The previously applied patches have been included in 1.9.48 and are
removed from the recipe and this repository.

Signed-off-by: Stefan Herbrechtsmeier <stefan@herbrechtsmeier.net>

As the license text of the xmlrpcpp changed, the license checksum
is adjusted.