Rename SymbolID to SymbolRef.  This is a precursor to some overhauling of the representation of symbolic values.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@60575 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/SVals.cpp b/lib/Analysis/SVals.cpp
index 524904d..6ee311c 100644
--- a/lib/Analysis/SVals.cpp
+++ b/lib/Analysis/SVals.cpp
@@ -29,9 +29,9 @@
   // FIXME: This is a rat's nest.  Cleanup.
 
   if (isa<loc::SymbolVal>(this))
-    return symbol_iterator(SymbolID((uintptr_t)Data));
+    return symbol_iterator(SymbolRef((uintptr_t)Data));
   else if (isa<nonloc::SymbolVal>(this))
-    return symbol_iterator(SymbolID((uintptr_t)Data));
+    return symbol_iterator(SymbolRef((uintptr_t)Data));
   else if (isa<nonloc::SymIntConstraintVal>(this)) {
     const SymIntConstraint& C =
       cast<nonloc::SymIntConstraintVal>(this)->getConstraint();