Try to fix buildbots

Apparently std::vector::erase(const_iterator) (as opposed to the
non-const iterator) is a part of C++11 but it seems this is not available
on all the buildbots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245900 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineBasicBlock.cpp

@@ -323,7 +323,8 @@ void MachineBasicBlock::printAsOperand(raw_ostream &OS,
 }
 
 void MachineBasicBlock::removeLiveIn(unsigned Reg) {
-  livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
+  std::vector<unsigned>::iterator I
+    = std::find(LiveIns.begin(), LiveIns.end(), Reg);
   if (I != LiveIns.end())
     LiveIns.erase(I);
 }