Removing '-e' flag from echo.

**Error**: When printing the warn message, it's prepended with "-e".
**Environment**: ```Linux ubuntu-server-1204-x64 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux```
**Repro**:
* Install this puppet module, which depends on concat: https://github.com/puppetlabs/puppet-postgresql
* Create a manifest with this configuration (or any, really):
```
node default {
    class { "postgresql::server":
      config_hash => {
        "listen_addresses" => "*"
      }
    }
}
```
* Puppet-apply your manifest and note that PostgreSQL won't start.
* Observe that the first line of pg_hba.conf (created by concat) is:
```
-e # This file is managed by Puppet. DO NOT EDIT.
```

I don't know why echo is printing that extra -e, but removing it fixes the warning message.  I realize that some people may want to have newlines in their default warning message.  Is there a better way to fix this?

Thanks!