gollvm: warning fix

Remove an unused local variable to fix a warning.

Change-Id: I2fac1cd56d2a032c459032c55c357442bb00f0a6
Reviewed-on: https://go-review.googlesource.com/c/145019
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/bridge/go-llvm.cpp b/bridge/go-llvm.cpp
index ba49ebe..6f0c34e 100644
--- a/bridge/go-llvm.cpp
+++ b/bridge/go-llvm.cpp
@@ -3008,7 +3008,6 @@
   bool changed = false;
   std::vector<llvm::Instruction*> newinsts;
   for (auto originst : expr->instructions()) {
-    llvm::BasicBlock *origblock = curblock;
     auto pair = postProcessInst(originst, curblock);
     auto inst = pair.first;
     if (inst != originst)