For reference deleter types the const qualifier on the return type of get_deleter() should be ignored, and a non-const deleter should be returned. This patch fixes a bug where "const deleter_type&" is incorrectly formed. git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@300121 91177308-0d34-0410-b5e6-96231b3b80d8