Constify all references to Stmt* and CFGBlock* in libChecker.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108811 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/BugReporterVisitors.cpp b/lib/Checker/BugReporterVisitors.cpp
index 776e12b..0323fe6 100644
--- a/lib/Checker/BugReporterVisitors.cpp
+++ b/lib/Checker/BugReporterVisitors.cpp
@@ -209,7 +209,7 @@
     ProgramPoint P = N->getLocation();
 
     if (BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
-      CFGBlock *BSrc = BE->getSrc();
+      const CFGBlock *BSrc = BE->getSrc();
       S = BSrc->getTerminatorCondition();
     }
     else if (PostStmt *PS = dyn_cast<PostStmt>(&P)) {
@@ -282,7 +282,7 @@
       ProgramPoint P = N->getLocation();
 
       if (BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
-        CFGBlock *BSrc = BE->getSrc();
+        const CFGBlock *BSrc = BE->getSrc();
         S = BSrc->getTerminatorCondition();
       }
       else if (PostStmt *PS = dyn_cast<PostStmt>(&P)) {