ovs-vsctl: Try connecting only once for active connections by default.
Until now, ovs-vsctl has kept trying to the database server until it
succeeded or the timeout expired (if one was specified with --timeout).
This meant that if ovsdb-server wasn't running, then ovs-vsctl would hang.
The result was that almost every ovs-vsctl invocation in scripts specified
a timeout on the off-chance that the database server might not be running.
But it's difficult to choose a good timeout. A timeout that is too short
can cause spurious failures. A timeout that is too long causes long delays
if the server really isn't running.
This commit should alleviate this problem. It changes ovs-vsctl's behavior
so that, if it fails to connect to the server, it exits unsuccessfully.
This makes --timeout obsolete for the purpose of avoiding a hang if the
database server isn't running. (--timeout is still useful to avoid a hang
if ovsdb-server is running but ovs-vswitchd is not, for ovs-vsctl commands
that modify the database. --no-wait also avoids that issue.)
Bug #2393.
Bug #15594. Reported-by: Jeff Merrick <jmerrick@vmware.com> Signed-off-by: Ben Pfaff <blp@nicira.com>