GitLab

Currently the code of poking progress engine to complete
requests and the code of cleanning up completed requests
are mixed up in one function rma_list_gc(), which is not
a clear code structure. We move the code of poking progress
engine out of rma_list_gc() and encapsule the code into
a separate function so that rma_list_gc() only does garbage
collection work.
Signed-off-by: Pavan Balaji <balaji@anl.gov>