Do not call SetPolicyServer(NULL), this is a programming error!
GetIdleConnectionToServer: Do not log ipaddr if it didn't resolve.
Verbose message was deceptive.
Fix redmine #2810

During bootstrapping the keys are created during the first promise pass, so
they need to be read from the files when the agent tries to connect to the
server in the second pass, else bootstrapping fails.
Don't try to connect without keys when bootstrapping

so that connection is tried on second or third promise pass of failsafe.
Don't give instructions for previous releases, we know we are running a current release.
Don't complain about bootstrapping failure if keys are not there

... since the keys will be generated from the "commands" promise.
Output error about missing key *before* generating it.
Merge branch 'bug2810' of git://github.com/jimis/core

Conflicts:
	libpromises/bootstrap.c
	libpromises/generic_agent.c