vyatta-cfg-system: formatting changes for style consistency

Update scripts/system/vyatta_update_resolv.pl to have consistent
identation levels and style throughout.
vyatta-cfg-system: prevent dhcp updating dns when statically configured

When DNS settings are statically configured, prevent DHCP interfaces
from appending to resolv.conf with additional name servers.  If the
system has been configured with a static name server, just use that
instead of accepting ISP provided name servers.  These can be accepted
again by simply deleting the statically configured name servers.

Bug #182 http://bugzilla.vyos.net/show_bug.cgi?id=182