Reading recovery.conf earlier

I'm planning to read recovery.conf earlier in the startup process, so we
can make a few things more "recovery aware". It's a nice-to-have only.

This won't be part of the HS patch though.

Proposal is to split out the couple of lines in
readRecoveryCommandFile() that set important state and make it read in
an option block that can be used by caller. It would then be called by
both postmaster (earlier in startup) and again later by startup process,
as happens now. I want to do it that way so I can read file before we
create shared memory, so I don't have to worry about passing details via
shared memory itself.

It will allow some tidy up in HS patch but isn't going to be intrusive.

Not thinking about lexers and stuff though at this stage, even if it is
on the todo list.

Any vetos?

--
Simon Riggs www.2ndQuadrant.com