[patch] Rename template parameter of std::__alloc_rebind

[Jonathan Wakely]

The name of this alias template is a copy&paste error, it should be
_Alloc. Tested powerpc64le-linux, committed to trunk.

commit a772309ec9fc300e57edd750fa32b8320d68004a
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Fri May 1 16:12:16 2015 +0100

    	* include/bits/alloc_traits.h (__alloc_rebind): Change parameter name.

diff --git a/libstdc++-v3/include/bits/alloc_traits.h b/libstdc++-v3/include/bits/alloc_traits.h
index d6c42ec..12c6c12 100644
--- a/libstdc++-v3/include/bits/alloc_traits.h
+++ b/libstdc++-v3/include/bits/alloc_traits.h
@@ -72,8 +72,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       typedef _Alloc<_Tp, _Args...> __type;
     };
 
-  template<typename _Ptr, typename _Tp>
-    using __alloc_rebind = typename __alloctr_rebind<_Ptr, _Tp>::__type;
+  template<typename _Alloc, typename _Tp>
+    using __alloc_rebind = typename __alloctr_rebind<_Alloc, _Tp>::__type;
 
   /**
    * @brief  Uniform interface to all allocator types.