Revert "Revert "adbd: switch the default USB implementation.""

This reverts commit 0d780391a1602535ff83bb80fd7f2c3f6a6848c2.

Reason for revert: cause for original revert probably fixed by https://android-review.googlesource.com/c/platform/system/core/+/914673

Change-Id: I9a7eead54fca3a1a9dfd93f650f01c056d39339e
diff --git a/adb/daemon/usb.cpp b/adb/daemon/usb.cpp
index f0e2861..69d1c31 100644
--- a/adb/daemon/usb.cpp
+++ b/adb/daemon/usb.cpp
@@ -628,9 +628,10 @@
 }
 
 void usb_init() {
-    if (!android::base::GetBoolProperty("persist.adb.nonblocking_ffs", false)) {
-        usb_init_legacy();
-    } else {
+    bool use_nonblocking = android::base::GetBoolProperty("persist.adb.nonblocking_ffs", true);
+    if (use_nonblocking) {
         std::thread(usb_ffs_open_thread).detach();
+    } else {
+        usb_init_legacy();
     }
 }