sniffer: check lengths of network device name and PID file path
sniffer: check lengths of network device name and PID file path

Coverity Scan reported that the ROHC sniffer didn't sanitize correctly
the following CLI parameters: network device name and PID file path.

The length of the network device name shall be in range [1 ; IFNAMESIZ[
The length of the PID file path shall be in range [1 ; PATH_MAX[
The length of the PID file name shall be in range [1 ; NAME_MAX[

didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc,didier-barvaux/rohc