multiple ros release support in rosdep.yaml

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The modular_cloud_matcher package requires yaml-cpp, which is installed in the ros-wide rosdep.yaml in electric but not in diamondback. For the latter, I had put an entry in our rosdep.yaml:

yaml-cpp:
ubuntu: yaml-cpp0.2.6-dev

This entry solves the problem for diamondback, but creates a conflict in electric:

[ rosmake ] rosdep install failed: QUITTING: due to conflicting rosdep definitions, please resolve this conflict.
Rules for yaml-cpp do not match:
{'apt': {'packages': ['yaml-cpp0.2.6-dev']}} [/opt/ros/electric/stacks/common_rosdeps/rosdep.yaml]
yaml-cpp0.2.6-dev [/opt/ros_addons/electric/stacks/ethzasl_mapping/rosdep.yaml]

Is there a way to specify rules specific to different ros releases in rosdep.yaml?