mxvipctl: Continue on error

Fixes #3

If /etc/mxstartups contains invalid port numbers (e.g. out of range),
mxvipctl aborts and other services, which have valid entries, will
also not be started:

    buczek@theinternet:~/git/mxstartup ((06ba2f6...))$ grep theinternet /etc/mxstartups
    test1 theinternet - /bin/true -[80:4432423]
    test2 theinternet - /bin/true -[80:8080]
    buczek@theinternet:~/git/mxstartup ((06ba2f6...))$ sudo mxstartupctl start
    starting /run/mariux/mxvip.test1.cfg ..
    adding forward 141.14.31.7:80 <-> 141.14.31.7:4432423
    iptables v1.6.0: Port `4432423' not valid

    Try `iptables -h' or 'iptables --help' for more information.
    starting /run/mariux/mxservice.test1.cfg ..
    starting /run/mariux/mxservice.test2.cfg ..
    buczek@theinternet:~/git/mxstartup ((06ba2f6...))$

Remove `-e` option of the shell.

mxvipctl

@@ -9,9 +9,6 @@ RUNDIR="/run/mariux"
 # expands *-pattern in pathnames to null if no matching files are found..
 shopt -s nullglob
 
-# exit on any error
-set -e
-
 function mxvip_start_one() {
    local vip=$1
    local -i i mip mfwd