Test db8 when no left free space on device

:Release Notes:
Test db8 behaviour when no enough free space on disk

:Detailed Notes:
This test allow test db8 when no free space left on device.
It works such way:
1. Create dir /tmp/db8-spam-test1
2. Create dir /tmp/db8-spam-test2
3. Mount 2M tmpfs to /tmp/db8-spam-test1
4. Mount 5M tmpfs to /tmp/db8-spam-test2
5. Open database /tmp/db8-spam-test1
6. Spam it (in threads) with random data
7. When no space left on tmpfs (2M), db8
   will recieve MojErrDbIO error. Test
   waiting for this error. If no error ocupired,
   test will fail
8. Close db (on device, where no left space)
9. Copy db to /tmp/db8-spam-test1 /tmp/db8-spam-test2
10. Open database /tmp/db8-spam-test2
11. Read data
12. Put data

:Testing Performed:
Compiled and tested localy.

QA Notes:

:Issues Addressed:
[ANG-260] [DB8] Add test of db8 behaviour, when no free space left
          on device

Open-webOS-DCO-1.0-Signed-off-by: Maksym Sditanov <maxim.sditanov@lge.com>

Change-Id: Ia34193ad73b111bd4e3c67a7c13924867551e109
Reviewed-on: https://g2g.palm.com/4318
Reviewed-by: Oleksii Uratkin <oleksii.uratkin@lge.com>
Tested-by: Oleksii Uratkin <oleksii.uratkin@lge.com>