LU-15484 tests: Increase timeout to wait for child

LU-15484 tests: Increase timeout to wait for child

Sanity-pcc 101a is failing because the remote 'sleep 600'
process is not always started in time, meaning the NS
doesn't exist.

Increase the wait time for this process to start.

Lustre-change: https://review.whamcloud.com/46764
Lustre-commit: TBD (20f794e7e8b736a944c9e1e87970e7232abd6a19)

Fixes: f3be560031 "LU-15170 llite: Switch pcc to lookup_one_len"

Test-Parameters: trivial
Test-Parameters: testlist=sanity-pcc env="ONLY=101a,ONLY_REPEAT=50"
Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: I57175ec2f0e948045cf88d4a13a1e56cc34f8407
Reviewed-on: https://review.whamcloud.com/47557
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>