LU-5079 tests: fix service_time in max_recovery_time()

This patch fixes the calculation of service_time in
max_recovery_time() to use the new method in
check_and_start_recovery_timer() and new values of
CONNECTION_SWITCH_MAX and CONNECTION_SWITCH_INC.

The patch also fixes replay-dual sub-tests:
- to call wait_clients_import_state() instead of sleeping
  uncertain time in test_11()
- to add some margin into the recovery time comparison
  in test_20()

Backport to b2_5 from master
Lustre-change: http://review.whamcloud.com/12724

Test-Parameters: alwaysuploadlogs \
envdefinitions=SLOW=yes,ENABLE_QUOTA=yes \
mdtfilesystemtype=ldiskfs mdsfilesystemtype=ldiskfs \
ostfilesystemtype=ldiskfs mdtcount=1 \
testlist=replay-dual,replay-dual

Test-Parameters: alwaysuploadlogs \
envdefinitions=SLOW=yes,ENABLE_QUOTA=yes \
mdtfilesystemtype=zfs mdsfilesystemtype=zfs \
ostfilesystemtype=zfs mdtcount=1 \
testlist=replay-dual,replay-dual

Test-Parameters: alwaysuploadlogs \
envdefinitions=SLOW=yes,ENABLE_QUOTA=yes \
mdtfilesystemtype=ldiskfs mdsfilesystemtype=ldiskfs \
ostfilesystemtype=ldiskfs mdtcount=4 \
testlist=replay-dual,replay-dual

Signed-off-by: Jian Yu <jian.yu@intel.com>
Change-Id: I8ff0385c508dc4aea883f4159f3f9e55a216527c
Reviewed-on: http://review.whamcloud.com/12714
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>