* seastar 6b21197...2ebe842 (6):
> Merge "Various improvements to execution stages" from Paweł
> app-template: allow apps to specify a name for help message
> bool_class: avoid initializing object of incomplete type
> app-template: make sure we can still get help with required options
> prometheus: Http handler that returns prometheus 0.4 protobuf or text format
> Update DPDK to 17.02
Includes patch from Pawel to adjust to updated execution_stage interface.
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