Do not send Nagios "Command Line" to alerta

[misho-s]

Is your feature request related to a problem? Please describe.
Nagios commands may contain sensitive informations. So it can be useful to have feature to prevent sending "Command Line" to Alerta.

[roffoNZ]

In alerta-neb.c you can change these to an empty string before building

"checkCommand", "",
"commandLine", ""

There are two places in the file.