update_engine: Fix TPM variable name max_kernel_rollfoward

- In a previous CL I named the variable incorrectly

BUG=chromium:814090
TEST=FEATURES=test emerge-samus update_engine

Change-Id: I17cbc85d42ba03040bfdae436cedd0238698b47e
Reviewed-on: https://chromium-review.googlesource.com/1059944
Commit-Ready: Zentaro Kavanagh <zentaro@chromium.org>
Tested-by: Zentaro Kavanagh <zentaro@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
diff --git a/hardware_android.cc b/hardware_android.cc
index 6812c71..7958fbf 100644
--- a/hardware_android.cc
+++ b/hardware_android.cc
@@ -175,8 +175,8 @@
   return -1;
 }
 
-bool HardwareAndroid::SetMaxKernelKeyRollforward(int max_kernel_rollforward) {
-  LOG(WARNING) << "STUB: Setting max_kernel_rollforward is not supported.";
+bool HardwareAndroid::SetMaxKernelKeyRollforward(int kernel_max_rollforward) {
+  LOG(WARNING) << "STUB: Setting kernel_max_rollforward is not supported.";
   return false;
 }