remove overwritten keys from hashes

[bcook-r7]

This fixes #6772. I chose to delete the overwritten hash values, rather than merge, since it was clear that the overwritten values were never tested (since they had no effect.)

Verification

• Visual code inspection (the fixes are fairly obvious)
• On an up-to-date Kali-rolling VM, verify that msfconsole does not throw warnings with the system ruby when running a fresh metasploit-framework checkout with this PR, OR....
• You can also simulate Kali's environment with RVM by updating to ruby 2.3.0 by modifying .ruby-version, reentering the directory, following rvm's instructions, then bundling the gems again.