delta_generator: Use "kernel" and "root" partition names internally

This commit abandons using "boot" and "system" names internally for
major version 1 payloads in favor of "kernel" and "root", which is
symmetrical with what's used in major version 2 payloads.

BUG=chromium:794404
TEST=no errors running brillo_update_payload with FORCE_MAJOR_VERSION
  set to either 1 or 2; paycheck.py <generated payload> --check and
  printing partition names in protobuf confirms correct names are
  generated

Change-Id: I396274812d5586e19a021c05b8b7a415aac976bf
Reviewed-on: https://chromium-review.googlesource.com/1119573
Commit-Ready: Tudor Brindus <tbrindus@chromium.org>
Tested-by: Tudor Brindus <tbrindus@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
diff --git a/omaha_response_handler_action_unittest.cc b/omaha_response_handler_action_unittest.cc
index 55c642b..7437f50 100644
--- a/omaha_response_handler_action_unittest.cc
+++ b/omaha_response_handler_action_unittest.cc
@@ -51,13 +51,13 @@
   void SetUp() override {
     FakeBootControl* fake_boot_control = fake_system_state_.fake_boot_control();
     fake_boot_control->SetPartitionDevice(
-        kLegacyPartitionNameKernel, 0, "/dev/sdz2");
+        kPartitionNameKernel, 0, "/dev/sdz2");
     fake_boot_control->SetPartitionDevice(
-        kLegacyPartitionNameRoot, 0, "/dev/sdz3");
+        kPartitionNameRoot, 0, "/dev/sdz3");
     fake_boot_control->SetPartitionDevice(
-        kLegacyPartitionNameKernel, 1, "/dev/sdz4");
+        kPartitionNameKernel, 1, "/dev/sdz4");
     fake_boot_control->SetPartitionDevice(
-        kLegacyPartitionNameRoot, 1, "/dev/sdz5");
+        kPartitionNameRoot, 1, "/dev/sdz5");
   }
 
   // Return true iff the OmahaResponseHandlerAction succeeded.