we do not need realpath for 1.8

Author: Oleg Sukhodolsky

lib/ruby-debug-ide/commands/breakpoints.rb

@@ -72,7 +72,7 @@ def realpath(filename)
         if defined?(JRUBY_VERSION)
           java.io.File.new(filename).canonical_path
         elsif RUBY_VERSION < '1.9'
-          Pathname.new(filename).realpath.to_s
+          filename
         else
           File.realpath(filename)
         end