pgsql: A collection of small fixes for logical replication.

A collection of small fixes for logical replication.

* Be sure to reset the launcher's pid (LogicalRepCtx->launcher_pid) to 0
even when the launcher emits an error.

* Declare ApplyLauncherWakeup() as a static function because it's called
only in launcher.c.

* Previously IsBackendPId() was used to check whether the launcher's pid
was valid. IsBackendPid() was necessary because there was the bug where
the launcher's pid was not reset to 0. But now it's fixed, so IsBackendPid()
is not necessary and this patch removes it.

Author: Masahiko Sawada
Reviewed-by: Kyotaro Horiguchi
Reported-by: Fujii Masao
Discussion: http://postgr.es/m/CAHGQGwFDWh_Qr-q_GEMpD+qH=vYPMdVqw=ZOSY3kX_Pna9R9SA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/280c53ecfbcad442c4b5eaab4cc3e65408f486eb

Modified Files
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src/backend/replication/logical/launcher.c | 19 +++++++++++++++++--
src/include/replication/logicallauncher.h | 1 -
2 files changed, 17 insertions(+), 3 deletions(-)