Use a constant for unset timeouts or deadlines

Previously there were some inconsistencies over whether to use -1 or 0
for `stime_t` values representing "unset" or "none". This change makes
all those cases use -1, and adds a constant to represent that.

TEST=unit tests and touch tests

Change-Id: If2d392da4da9c58bf4e6969c1f37ab4b746f4483
Tested-by: Harry Cutts <>
Reviewed-by: Sean O'Brien <>
Commit-Queue: Harry Cutts <>
19 files changed