[rubygems/rubygems] Remove LoadError message in regards to requiring a relative file

Ruby 1.9.2 removed "." from LOAD_PATH for robustness and security reasons.
This code was introduced by 56fc830e19 commit
to helping users understand the issue and had a guard condition to include the message for `RUBY_VERSION >= "1.9"`.
However, the guard condition was removed as part of the "Ruby version leftover" cleanup by
8c9cf76e41

Ruby 1.9 development was ended a long time ago and this message is not useful anymore.

https://github.com/rubygems/rubygems/commit/a23609b15a

lib/bundler.rb

@@ -653,10 +653,6 @@ EOF
     rescue ScriptError, StandardError => e
       msg = "There was an error while loading `#{path.basename}`: #{e.message}"
 
-      if e.is_a?(LoadError)
-        msg += "\nDoes it try to require a relative path? That's been removed in Ruby 1.9"
-      end
-
       raise GemspecError, Dsl::DSLError.new(msg, path, e.backtrace, contents)
     end
 

spec/bundler/runtime/setup_spec.rb

@@ -1066,7 +1066,6 @@ end
 
       expect(err.lines.map(&:chomp)).to include(
         a_string_starting_with("[!] There was an error while loading `bar.gemspec`:"),
-        a_string_starting_with("Does it try to require a relative path? That's been removed in Ruby 1.9."),
         " #  from #{default_bundle_path "bundler", "gems", "bar-1.0-#{ref[0, 12]}", "bar.gemspec"}:1",
         " >  require 'foobarbaz'"
       )