fix egrep rule and ncat rule

[dms1lva]

fixed the grep binaries list that had egre instead of egrep
added the ncat command line arguments -c and -e that can be used to spawn remote shells

Launching this : ncat -l localhost 4443 -e "/bin/ls"

would not match anything when running: sudo sysdig "proc.name = \"ncat\" and (proc.args contains \"--sh-exec\" or proc.args contains \"--exec\")"

using sudo sysdig "proc.name = \"ncat\" and (proc.args contains \"--sh-exec\" or proc.args contains \"--exec\" or proc.args contains \"-e\")" fixes this

[mstemm]

The cause of the test failures was a recent sysdig change that I fixed with #646, and not due to the rules, so I'll go ahead and merge.