Add Meterpreter bins for release branch.

This contains the same bins as #3423, but it is targeted at the release
branch for rapid7/metasploit-framework.
Roll back the jar/py changes
Land #3425 from todb-r7:release-meterpreter-bins
Merge branch 'release'

Updates meterpreter bins and closes #3425 and #3423.
Bump version to 4.9.3
Merge branch 'release' into 'master'
Update version spec
Merge branch 'release'