Suppress unused capture warning in CheckCopy

Werror bots didn't like the lambda + assert thing in my previous commit.

Capture everything to suppress the error.

Example failure here:
http://lab.llvm.org:8011/builders/lld-x86_64-darwin13/builds/29393

llvm-svn: 352124
diff --git a/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp b/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
index f08439c..e1536de 100644
--- a/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
@@ -485,7 +485,7 @@
   // Returns true, or asserts if something we don't expect happens. Instead of
   // returning true, we return isValidCopy() to ensure that we verify the
   // result.
-  auto CheckCopy = [&I, &DstRegBank, &MRI, &TRI, &RBI, &KnownValid]() {
+  auto CheckCopy = [&]() {
     // If we have a bitcast or something, we can't have physical registers.
     assert(
         I.isCopy() ||