adb: fix use of wrong union variant.

Also, prepare to add more compression flags.

Bug: https://issuetracker.google.com/150827486
Test: none
Change-Id: I5044e5d5944aff5c18241fd7439baa48e2e09980
diff --git a/adb/daemon/file_sync_service.cpp b/adb/daemon/file_sync_service.cpp
index dcd640b..3138ab4 100644
--- a/adb/daemon/file_sync_service.cpp
+++ b/adb/daemon/file_sync_service.cpp
@@ -558,11 +558,13 @@
     }
 
     std::optional<CompressionType> compression;
+
+    uint32_t orig_flags = msg.send_v2_setup.flags;
     if (msg.send_v2_setup.flags & kSyncFlagBrotli) {
         msg.send_v2_setup.flags &= ~kSyncFlagBrotli;
         if (compression) {
             SendSyncFail(s, android::base::StringPrintf("multiple compression flags received: %d",
-                                                        msg.recv_v2_setup.flags));
+                                                        orig_flags));
             return false;
         }
         compression = CompressionType::Brotli;
@@ -676,11 +678,12 @@
     }
 
     std::optional<CompressionType> compression;
+    uint32_t orig_flags = msg.recv_v2_setup.flags;
     if (msg.recv_v2_setup.flags & kSyncFlagBrotli) {
         msg.recv_v2_setup.flags &= ~kSyncFlagBrotli;
         if (compression) {
             SendSyncFail(s, android::base::StringPrintf("multiple compression flags received: %d",
-                                                        msg.recv_v2_setup.flags));
+                                                        orig_flags));
             return false;
         }
         compression = CompressionType::Brotli;