pgsql: Adjust comment about timeout when waiting for WAL at recovery

Adjust comment about timeout when waiting for WAL at recovery

A timeout of 5s is used when waiting for WAL to become available at
recovery so as the startup process is able to react promptly if a
trigger file shows up.  However this missed the fact that the startup
process also relies on the timeout to check periodically the status of
any active WAL receiver.

Discussion: https://postgr.es/m/20190131070956.GE13429@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/c93001b3f957994942ea18ed261ae06ac507ea95

Modified Files
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src/backend/access/transam/xlog.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)