Bug/msp 11050/rails root

Fixes the Rails Engine root so that it points to the correct install root
This is what it would be set to if you called one of the binaries from inside that directory, but if you call it from elsewhere it may get set to CWD and cause path loading to fail

VERIFICATION STEPS
- [x] go to a directory other than framework root
- [x] launch msfcli with an absolute path and the following arguments `auxiliary/fuzzers/ntp/ntp_protocol_fuzzer S`
- [x] VERIFY you do not see the `Error: Invalid module: auxiliary/fuzzers/ntp/ntp_protocol_fuzzer`
- [x] launch msfconsole
- [ ] get a meterpreter shell
- [ ] VERIFY nothing blows up