Workaround module test failures by removing the version info from module hashes.

PR12196: The module hash strings are not actually hashing the compiler version
string; the entire version string is being included in the hash.  Depending on
the module cache directory name, that can lead to failures where the path
names become too long.  As a temporary workaround, just remove the version
string from the hash.

llvm-svn: 152266
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 7038e85..9ccd9b2 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2196,7 +2196,10 @@
   ModuleSignature Signature;
   
   // Start the signature with the compiler version.
-  Signature.add(getClangFullRepositoryVersion());
+  // FIXME: The full version string can be quite long.  Omit it from the
+  // module hash for now to avoid failures where the path name becomes too
+  // long.  An MD5 or similar checksum would work well here.
+  // Signature.add(getClangFullRepositoryVersion());
   
   // Extend the signature with the language options
 #define LANGOPT(Name, Bits, Default, Description) \