Don't pass a guid to MetadataBuilder::AddPartition.

GUIDs are being removed from the super partition, so remove
update_engine code that uses them.

Bug: 117229984
Test: update_engine_unittests --gtest_filter=*BootControlAndroid*
Change-Id: Ia91e7bed8e5d25535e568fa2aa9cb8854479156a
diff --git a/boot_control_android_unittest.cc b/boot_control_android_unittest.cc
index 9744b42..ea5e808 100644
--- a/boot_control_android_unittest.cc
+++ b/boot_control_android_unittest.cc
@@ -48,7 +48,6 @@
 constexpr const char* kFakeDevicePath = "/fake/dev/path/";
 constexpr const char* kFakeMappedPath = "/fake/mapped/path/";
 constexpr const uint32_t kFakeMetadataSize = 65536;
-constexpr const char* kZeroGuid = "00000000-0000-0000-0000-000000000000";
 
 // A map describing the size of each partition.
 using PartitionSizes = std::map<std::string, uint64_t>;
@@ -97,7 +96,7 @@
   if (builder == nullptr)
     return nullptr;
   for (const auto& pair : sizes) {
-    auto p = builder->AddPartition(pair.first, kZeroGuid, 0 /* attr */);
+    auto p = builder->AddPartition(pair.first, 0 /* attr */);
     EXPECT_TRUE(p && builder->ResizePartition(p, pair.second));
   }
   return builder;