The AMD package seems to be corrupt or incomplete. At least one package is missing:
Unable to locate package opencl-legacy-amdgpu-pro-icd
(The rest of the errors, the unmet dependencies, seem to originate from manually installing the wrong version 'opencl-amdgpu-pro')
Best to open a bugreport on launchpad.net mentioning the error 'Unable to locate package opencl-legacy-amdgpu-pro-icd'
Also open a bugreport on bugzilla.freedesktop.org
Several AMD linux-devs are regulars on bugzilla and they always help out where they can.
I have very fond memories of the time I had some problems, after a kernel update, to get an ancient AMD GPU working that was already more than a decade out of production.
I filed a bugreport and before I knew it I had contact with the main devs from AMD HQ in Germany who offered lots of help. Following my findings they incorporated patches for it in the driver tree in no time.
You can imagine that that was a totally stunning but very joyful experience. 
I think my next video card on Linux will be a NVIDIA
Understandably so. OpenCL on nVidia is more mature at the moment.
For gaming on Linux though, I would choose AMD over nVidia any day.