BasicBlock::getContext can no longer return a NULL so update the doc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79432 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/BasicBlock.h b/include/llvm/BasicBlock.h
index 9138d28..3ba4e36 100644
--- a/include/llvm/BasicBlock.h
+++ b/include/llvm/BasicBlock.h
@@ -86,8 +86,7 @@
   explicit BasicBlock(LLVMContext &C, const Twine &Name = "",
                       Function *Parent = 0, BasicBlock *InsertBefore = 0);
 public:
-  /// getContext - Get the context in which this basic block lives,
-  /// or null if it is not currently attached to a function.
+  /// getContext - Get the context in which this basic block lives.
   LLVMContext &getContext() const;
   
   /// Instruction iterators...