Remove trivial destructor from SVal.

This enables the faster SmallVector in clang and also allows clang's unused
variable warnings to be more effective. Fix the two instances that popped up.

The RetainCountChecker change actually changes functionality, it would be nice
if someone from the StaticAnalyzer folks could look at it.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160444 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp b/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
index a156f0d..c44fc67 100644
--- a/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/RetainCountChecker.cpp
@@ -3168,7 +3168,7 @@
     // If the receiver is unknown, conjure a return value.
     SValBuilder &SVB = C.getSValBuilder();
     unsigned Count = C.getCurrentBlockCount();
-    SVal RetVal = SVB.getConjuredSymbolVal(0, CE, LCtx, ResultTy, Count);
+    RetVal = SVB.getConjuredSymbolVal(0, CE, LCtx, ResultTy, Count);
   }
   state = state->BindExpr(CE, LCtx, RetVal, false);