Use the InstalledDir correctly, and test it correctly as well. =/ Should
have noticed this previously, sorry.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@141167 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 0e9dcd1..eab76d5 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -1589,7 +1589,7 @@
                                          D.PrefixDirs.end());
     Prefixes.push_back(D.SysRoot);
     Prefixes.push_back(D.SysRoot + "/usr");
-    Prefixes.push_back(D.InstalledDir);
+    Prefixes.push_back(D.InstalledDir + "/..");
 
     // Loop over the various components which exist and select the best GCC
     // installation available. GCC installs are ranked by version number.