Read stats for backlog verifies not reported for time-expired workloads

Read stats for backlog verifies not reported for time-expired workloads

When verify_backlog is used on a write-only workload with a runtime= value
and the runtime expires before the workload has written its full dataset,
the read stats for the backlog verifies are not reported, resulting in a
stat result showing only the workload writes (ie, the "read:" results
section is completely missing from fio's stats output)

The logic in thread_main() fails to call update_runtime() for DDIR_READ
because the existing call to update_runtime() for DDIR_READ on write-only
workloads is currently only done after do_verify() is complete, which wont
be called in this scenario because td->terminate is true due to the
expiration of the runtime.

Link: https://github.com/axboe/fio/issues/1515
Signed-off-by: Adam Horshack (horshack@live.com)