Revert r109428 "Hoist argument type checking into CheckFormatHandler.  This is prep for scanf format"

Got errors about ASTContext being undefined with Visual Studio 2010.

llvm-svn: 109491
diff --git a/clang/lib/Analysis/FormatString.cpp b/clang/lib/Analysis/FormatString.cpp
index 2c012d3..0fbe543 100644
--- a/clang/lib/Analysis/FormatString.cpp
+++ b/clang/lib/Analysis/FormatString.cpp
@@ -379,11 +379,9 @@
 }
 
 //===----------------------------------------------------------------------===//
-// Methods on FormatSpecifier.
+// Methods on ConversionSpecifier.
 //===----------------------------------------------------------------------===//
 
-FormatSpecifier::~FormatSpecifier() {}
-
 bool FormatSpecifier::hasValidLengthModifier() const {
   switch (LM.getKind()) {
     case LengthModifier::None: