I just checked your photos one more time and i see that you have wrong rspec-mocks version installed (yours is 2.14.4). Because when i check my system i get:
Command:
gem list -d rspec-mocksrspec-mocks (2.14.3, 2.14.2, 2.13.0)
Authors: Steven Baker, David Chelimsky
Rubyforge:
http://rubyforge.org/projects/rspec Homepage:
http://github.com/rspec/rspec-mocks License: MIT
Installed at (2.14.3): /var/lib/gems/1.9.1
(2.14.2): /var/lib/gems/1.9.1
(2.13.0): /var/lib/gems/1.9.1
rspec-mocks-2.14.3
On wpscan developers site i see that maybe this can help:
sudo gem install bundler && bundle install --without test development (but i can't test because i don't have this issue)
If this don't work, try to remove wrong gem version (1.install wpscan again, run upgrade, but don't try to use tool, even if you get install errors).
sudo gem uninstall rspec-mocks -v 2.14.4
sudo gem install rspec-mocks -v 2.14.3I guess that gem was updated in global repository, but wpscan developer didn't upgrade his tool. Who knows

Cheers !