Obex: Squashed commit of the following

Obex : Reduce MTU Size.

Use case:
1. Start Low Latency and High Tx Power adv from the DUT
2. From a 2nd DUT scan, connect and pair with the LEP DUT
3. Connect the DUT to a SCO HS
4. Connect the DUT to 2 BR/EDR HID devices
5. Start MO call from the DUT going over SCO
6. Start sending a file from Phone over OPP to the DUT

Result:
After a while the OPP link disconnects
reason: "Connection Timeout"

Fix:
Reduce Obex MTU to 8k if reduce MTU is enable
Change-Id: I21cb27ff98e07cd923d6e28a67b3b52835b68956

OBEX: Dynamic VERBOSE level logging for OBEX.
- Support runtime VERBOSE level logging control
  for  OBEX lib.
- Added extra informative logs useful to
  debug issues from Obex layer.

Change-Id: If94c88b438b3c283aca0ba4cc46f42bb1d8c37eb

OBEX : Handle Negative index Exception

Use case:
1. Send file to remote device.
2. Wait for accepting the file transfer on remote device.
   Use Specific remote device(that sends some
      optional headers).

Failure:
No file acceptance popup seen on remote device.

Root cause:
Failure in com.android.bluetooth.

FATAL EXCEPTION: BtOpp ClientThread
Process: com.android.bluetooth, PID: 22527
  java.lang.NegativeArraySizeException: -3
  at javax.obex.ObexHelper.updateHeaderSet(ObexHelper.java:216)
  at javax.obex.ClientSession.sendRequest(ClientSession.java:568)
  at javax.obex.ClientSession.connect(ClientSession.java:148)
  at com.android.bluetooth.opp.BluetoothOppObexClientSession$ClientThread.
  connect(BluetoothOppObexClientSession.java:317)
  at com.android.bluetooth.opp.BluetoothOppObexClientSession$ClientThread.
  run(BluetoothOppObexClientSession.java:231)
  am_craash( 1402): [22527,0,com.android.bluetooth,818462277,java.lang.
  NegativeArraySizeException,-3,ObexHelper.java,216]

Fix:
Add length check before allocate memory and break loop if length is less than
expected header length as per OBEX Specification.

CRs-Fixed: 2197150
Change-Id: I805e6b1d51f69645d5132c3c18db2e752d04b096