Include <sys/capaibility.h> to get _LINUX_CAPABILITY_VERSION defined.

It's no longer used in version_info.c, but is used in the main source
files of TShark and Wireshark (it's already included in dumpcap).

Change-Id: I2169a2bbed678baf26fc8711d7c13d95cce3ee2a
Reviewed-on: https://code.wireshark.org/review/2819
Reviewed-by: Guy Harris <guy@alum.mit.edu>