Fix revoke command in database.pp to support postgres 8.1

In postgres 8.1, the 'CONNECT' privilege doesn't exist, which
would result in an error if you tried to use the 'database'
type.  This commit conditions the revoke statement to use the
'ALL' privilege on 8.1.
Merge pull request #83 from cprice-puppet/bug/master/82-pg-8.1-connect-privilege

Fix revoke command in database.pp to support postgres 8.1