BasicManagement Ping: add ping command support - v2

- Improved parsing safety
- I'll create an issue to keep track that we have to find a solution for the busybox ping which actually do not support some of the options used in the current implementation:
 W, i and Q

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- Add the ping command support: build and call the system command,
parse its result output.
- Fix a typo in update_test_ids_lists() funtion in file
rygel-basic-management.vala

Signed-off-by: Christophe Guiraud <christophe.guiraud@intel.com>