vyatta-cfg-system: formatting changes for style consistency

Update scripts/vyatta-address to have consistent identation levels and
style throughout.
vyatta-cfg-system: allow interfaces with dhcp addresses to be deleted

Update the checks in scripts/vyatta-address to allow the deletetion of
an interface that has a DHCP address.  The patch put in place for
Bug #259 (http://bugzilla.vyos.net/show_bug.cgi?id=259) checks that an
interface exists before preceding with the delete, but this chokes when
supplied with the address 'dhcp'.

This patch checks if the supplied interface is a DHCP address, before
extracting the IP address and then using that address for the check.

Bug #305 http://bugzilla.vyos.net/show_bug.cgi?id=305
Merge remote-tracking branch 'upstream/helium' into helium
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
Merge pull request #21 from cyclops8456/helium

vyatta-cfg-system: Bug #182 and #305