Delete obsolete comment.

Swift SVN r26984

lib/SILAnalysis/CallGraphAnalysis.cpp

@@ -35,9 +35,6 @@ llvm::cl::opt<bool> DumpCallGraph("sil-dump-call-graph",
                                   llvm::cl::init(false), llvm::cl::Hidden);
 
 CallGraph::CallGraph(SILModule *Mod, bool completeModule) : M(*Mod) {
-  // Build the initial call graph by creating a node for each
-  // function, and an edge for each direct call to a free function.
-
   ++NumCallGraphsBuilt;
 
   unsigned NodeOrdinal = 0;