Return UnknownVal in RegionStoreManager::getSizeInElements() for unsupported regions.  This silences a warning when compiling Release-Asserts builds.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61818 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/RegionStore.cpp b/lib/Analysis/RegionStore.cpp
index 602d6bd..4e0215b 100644
--- a/lib/Analysis/RegionStore.cpp
+++ b/lib/Analysis/RegionStore.cpp
@@ -431,6 +431,7 @@
   }
 
   assert(0 && "Other regions are not supported yet.");
+  return UnknownVal();
 }
 
 /// ArrayToPointer - Emulates the "decay" of an array to a pointer