OPP: Standardize date in dump()

Match the output in logcat/bug reports.

"MM-dd HH:mm:ss"

Profile: BluetoothOppService
  Shares:
    01-16 22:38:40 -> 0/1800301
    01-16 22:39:23 -> 0/1800301
    01-17 17:43:34 -> 1800301/1800301

Test: adb shell dumpsys bluetooth_manager
Change-Id: I39f904afe8a7b245cdf4fe6d1a6e93ef584f13a9