Update language to comply with Android's inclusive language guidance

More details in: https://source.android.com/setup/contribute/respectful-code

Bug: 161896447
Test: build, run unittests
Change-Id: I8d666eee75490146eb57a183f0cfdf343b58b602
diff --git a/payload_generator/payload_file.h b/payload_generator/payload_file.h
index 0c3e9d5..d1f8196 100644
--- a/payload_generator/payload_file.h
+++ b/payload_generator/payload_file.h
@@ -60,9 +60,9 @@
   // Computes a SHA256 hash of the given buf and sets the hash value in the
   // operation so that update_engine could verify. This hash should be set
   // for all operations that have a non-zero data blob. One exception is the
-  // dummy operation for signature blob because the contents of the signature
+  // fake operation for signature blob because the contents of the signature
   // blob will not be available at payload creation time. So, update_engine will
-  // gracefully ignore the dummy signature operation.
+  // gracefully ignore the fake signature operation.
   static bool AddOperationHash(InstallOperation* op, const brillo::Blob& buf);
 
   // Install operations in the manifest may reference data blobs, which