vpnor: Fix SEGV fault in vpnor

Table object may throw error hence initialize table pointer to null so
that vpnor_free() doesn't free the junk pointer.
In vpnor_free() do not free table pointer if it

vpnor: Fix SEGV fault in vpnor

Table object may throw error hence initialize table pointer to null so
that vpnor_free() doesn't free the junk pointer.
In vpnor_free() do not free table pointer if its null.

Added testcase to make sure the issue is fixed.
```
PASS: vpnor/test/toc_missing_file_reset
```

Change-Id: Ic6f4a7d163cf786d71b810190ab6ede0cd3a0717
Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>

show more ...