Revert "adb: turn on libusb by default."

This reverts commit f2f0b318.

libusb seems to be causing flakiness on some machines. Disable it for
now.

Bug: http://b/62962248
Test: python test_device.py (with DeviceOfflineTest commented out)
Change-Id: Ia9de78ab772c22574cf5ca7facb78f22af6d7a71
(cherry picked from commit 969110ca)

parent 712b628d

adb/transport_usb.cpp

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -192,7 +192,7 @@ bool should_use_libusb() {
	#if defined(_WIN32) \|\| !ADB_HOST		#if defined(_WIN32) \|\| !ADB_HOST
	return false;		return false;
	#else		#else
	static bool disable = getenv("ADB_LIBUSB") && strcmp(getenv("ADB_LIBUSB"), "0") == 0;		static bool enable = getenv("ADB_LIBUSB") && strcmp(getenv("ADB_LIBUSB"), "1") == 0;
	return !disable;		return enable;
	#endif		#endif
	}		}