Issue: Can't Authenticate to Metasploit [MSF Integration]

The issue is summarized well in PR#519:

Serpico >=1.2.2 uses a newer version of msfrpc-client (1.1.1) which breaks the ability to authenticate with msfrpcd. Serpico version 1.2.1 used msfrpc-client 1.0.3, and is the last known working release. To fix, msfrpc-client downgrade to v1.0.3 in the Gemfile and Gemfile.lock files, and [make] the appropriate additional dependences (librex and msgpack) were adjusted to accommodate the change.

To fix the issue:

1. in Gemfile change:

gem 'msfrpc-client', '1.1.1'

to

gem 'msfrpc-client', '1.0.3'

2. in Gemfile.lock change:

    msfrpc-client (1.1.1)	    
      msgpack (~> 1)	      
      rex (~> 2)	      
    msfrpc-client (= 1.1.1)

    msfrpc-client (1.0.3)
      msgpack (~> 0.5.8)
      librex (~> 0.0.70)
    msfrpc-client (= 1.0.3)