pgsql: Remove empty function BufmgrCommit().

Remove empty function BufmgrCommit().

This function has been a no-op for over a decade. Even if bufmgr
regains a need to be called during commit, it seems unlikely that
the most appropriate call points would be precisely here, so it's not
doing us much good as a placeholder either. Now, removing it probably
doesn't save any noticeable number of cycles --- but the main call is
inside the commit critical section, and the less work done there the
better.

Matthias van de Meent

Discussion: https://postgr.es/m/CAEze2Wi1=tLKbxZnXzcD+8fYKyKqBtivVakLQC_mYBsP4Y8qVA@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/58c9600a9f5818f63712ae4262143c42517dcba7

Modified Files
--------------
src/backend/access/transam/xact.c | 12 +++---------
src/backend/storage/buffer/bufmgr.c | 10 ----------
src/include/storage/bufmgr.h | 1 -
3 files changed, 3 insertions(+), 20 deletions(-)