pgsql: Ensure walsenders can be SIGTERMed while in non-walsender code

Ensure walsenders can be SIGTERMed while in non-walsender code

In oder to exit on SIGTERM when in non-walsender code,
such as do_pg_stop_backup(), we need to set the interrupt
variables that are used there, and not just the walsender
local ones.

Branch
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REL9_1_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/5df22bba644d1c083118942292097ba2395fad15

Modified Files
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src/backend/replication/walsender.c |    7 +++++++
1 files changed, 7 insertions(+), 0 deletions(-)