Remove no longer necessary code

[deivid-rodriguez]

What was the end-user or developer problem that led to this PR?

#7371 introduced a potential NoMethodError in the gem rdoc command. See 34df962#r1449105511.

What is your fix for the problem, implemented in this PR?

I believe this code is no longer necessary.

It was introduced a long time ago at e6e3c79. I guess "pseudo gems" meant default gems, and indeed passing a default gem to gem rdoc does not seem to generate any documentation nor log messages, however, it does not cause this rescue to be triggered, so I think rdoc must be swallowing whatever error internally.

Make sure the following tasks are checked

• Describe the problem / feature
• Write tests for features and bug fixes
• Write code to solve the problem
• Make sure you follow the current code style and write meaningful commit messages without tags