[rubygems/rubygems] Remove unnecessary error handling

These gems always define their main namespace and I don't think that
will ever change.

ruby/rubygems@6663cbed53

Author: deivid-rodriguez

lib/bundler/cli/console.rb

@@ -32,9 +32,6 @@ def get_constant(name)
         "irb" => :IRB,
       }[name]
       Object.const_get(const_name)
-    rescue NameError
-      Bundler.ui.error "Could not find constant #{const_name}"
-      exit 1
     end
   end
 end