IncludeFixerTest.cpp: Tweak not to assume clang-tools-extra were onto clang/tools/extra.

llvm-svn: 266874
diff --git a/clang-tools-extra/unittests/include-fixer/IncludeFixerTest.cpp b/clang-tools-extra/unittests/include-fixer/IncludeFixerTest.cpp
index 75ee8a3..1275976 100644
--- a/clang-tools-extra/unittests/include-fixer/IncludeFixerTest.cpp
+++ b/clang-tools-extra/unittests/include-fixer/IncludeFixerTest.cpp
@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "../../../../unittests/Tooling/RewriterTestContext.h"
+#include "unittests/Tooling/RewriterTestContext.h"
 #include "InMemoryXrefsDB.h"
 #include "IncludeFixer.h"
 #include "clang/Tooling/Tooling.h"