Rename _LIBCPP_DEBUG2 to _LIBCPP_DEBUG.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@189140 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/strings/basic.string/string.modifiers/string_erase/erase_iter_iter_db2.pass.cpp b/test/strings/basic.string/string.modifiers/string_erase/erase_iter_iter_db2.pass.cpp
index dfc29ef..13f97b4 100644
--- a/test/strings/basic.string/string.modifiers/string_erase/erase_iter_iter_db2.pass.cpp
+++ b/test/strings/basic.string/string.modifiers/string_erase/erase_iter_iter_db2.pass.cpp
@@ -11,7 +11,7 @@
 
 // Call erase(const_iterator first, const_iterator last); with second iterator from another container
 
-#if _LIBCPP_DEBUG2 >= 1
+#if _LIBCPP_DEBUG >= 1
 
 #define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : std::exit(0))