LU-13216 ptlrpc: sptlrpc_req_refresh_ctx's timeout semantic

LU-13216 ptlrpc: sptlrpc_req_refresh_ctx's timeout semantic

sptlrpc_req_refresh_ctx() is only called with two possible timeouts
in the current code: either we do not wait at all, or we wait
indefinitely.
So change semantic of sptlrpc_req_refresh_ctx()'s timeout parameter,
to be more consistent with wait* primitives. timeout == 0 means
'do not wait at all', and timeout == MAX_SCHEDULE_TIMEOUT means
'wait indefinitely'. Other timeout values are unsupported.

Consequently, remove code that handles the case of a non zero and
non infinite timeout. And remove the unsed ctx_refresh_timeout()
callback.
It solves a problem in the current code, because in case of indefinite
wait, sptlrpc_req_refresh_ctx() is not supposed to try to refresh the
request, so it must not call the ctx_refresh_timeout() callback.

Fixes: c1fad6a9a5 ("LU-10467 ptlrpc: convert waiting in sptlrpc_req_refresh_ctx()")
Test-Parameters: trivial envdefinitions=SHARED_KEY=true testlist=sanity-sec
Test-Parameters: envdefinitions=SHARED_KEY=true testlist=sanity-sec
Test-Parameters: envdefinitions=SHARED_KEY=true testlist=sanity-sec
Test-Parameters: envdefinitions=SHARED_KEY=true testlist=sanity-sec
Test-Parameters: envdefinitions=SHARED_KEY=true testlist=sanity-sec
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I1b20457c86863d57f97f4d998f7c5fa8ec928b31
Reviewed-on: https://review.whamcloud.com/37473
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: Maloo <maloo@whamcloud.com>
Tested-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>