fixed debug_method for assignment methods
fixed debug_method for assignment methods

git-svn-id: 9e3efa61edebcacd56b2e0a91989aa186199d37f@19 453b2852-3d18-0410-866e-d09c099698e4

ruby-debug/ruby-debug,ruby-debug/ruby-debug,gfowley/ruby-debug,ruby-debug/ruby-debug,gfowley/ruby-debug,gfowley/ruby-debug