[torsocks] Detect elevated capability executables

Before:

$ torsocks ping torproject.org PING torproject.org (154.35.132.70) 56(84) bytes of data. 64 bytes from archeotrichon.torproject.org (154.35.132.70): icmp_seq=1 ttl=52 time=235 ms 64 bytes from archeotrichon.torproject.org (154.35.132.70): icmp_seq=2 ttl=52 time=166 ms 64 bytes from archeotrichon.torproject.org (154.35.132.70): icmp_seq=3 ttl=52 time=155 ms

After:

$ torsocks /bin/ping ERROR: /bin/ping gains the following elevated capabilities. torsocks will not work with privledged executables. /bin/ping = cap_net_raw+ep

Trac:
Username: shawnl

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