sshkey uses name instead of title for duplication check

Describe the Bug

With 2 resources named pxe-example.com and dhcp-example.com I get duplicate definition error. The target and title are different in both. The rest is the same.

sshkey { 'pxe-example.com':
    ensure => 'present',
    name   => 'example.com',
    type   => 'ssh-rsa',
    key    => '<redacted>',
    target => '/var/lib/<user>/.ssh/known_hosts',
}

In an environment where sshd is intentionally configured to not read a global known hosts file, attempting to change the resource title for the same key installed into different locations fails.

Cannot alias Sshkey[pxe-example.com] to ["example.com"] at /etc/puppetlabs/code/environments/dhcp/site/role/manifests/pxe.pp:56; resource ["Sshkey", "example.com"] already declared at /etc/puppetlabs/code/environments/dhcp/site/role/manifests/dhcp.pp:73 at /etc/puppetlabs/code/environments/dhcp/site/role/manifests/pxe.pp:56:3 on node dhcp-failover.err.internal

Expected Behavior

Expected behavior is that changing the title suffices in it being a different resource.

Steps to Reproduce

See above.

Environment

• Version puppetserver-2.7.2-1.el6.noarch (2.7.2)/puppet-agent-1.9.3-1.el6.x86_64 (4.9.4)
• Platform CentOS 6.8/6.9

Additional Context

This was originally filed as MODULES-7610.

Start by reproducing the duplicate-definition error with the two sshkey resources described in the issue, using different titles and targets. Trace the sshkey resource's duplication or alias handling and verify that distinct titles are accepted while identical definitions remain protected. Done means changing the title no longer causes a duplicate resource error for keys installed in different locations.