update rubyntlm to use the released gem

Author: Brent Cook

Gemfile

@@ -5,7 +5,6 @@ gemspec name: 'metasploit-framework'
 
 gem 'bit-struct', git: 'https://github.com/busterb/bit-struct', branch: 'ruby-2.4'
 gem 'method_source', git: 'https://github.com/banister/method_source', branch: 'master'
-gem 'rubyntlm', git: 'https://github.com/WinRb/rubyntlm', branch: 'master'
 
 # separate from test as simplecov is not run on travis-ci
 group :coverage do

Gemfile.lock

@@ -1,10 +1,3 @@
-GIT
-  remote: https://github.com/WinRb/rubyntlm
-  revision: 38aaf1d59dd1a443e4a9c0aea2be232cfe262772
-  branch: master
-  specs:
-    rubyntlm (0.6.2)
-
 GIT
   remote: https://github.com/banister/method_source
   revision: 0cc6cc8e15d08880585e8cb0c54e13c3cf937c54
@@ -354,6 +347,7 @@ GEM
       bindata
       rubyntlm
       windows_error
+    rubyntlm (0.6.1)
     rubyzip (1.2.1)
     sawyer (0.8.1)
       addressable (>= 2.3.5, < 2.6)
@@ -402,7 +396,6 @@ DEPENDENCIES
   rake
   redcarpet
   rspec-rails
-  rubyntlm!
   shoulda-matchers
   simplecov
   timecop