Take the dash compatible IPv6 link-local address test from the Debian
version of dhclient-script.
Note that although "echo -e" in the OE version of dhclient-script is
technically bash specific too, it is supported by Busybox echo when
Busybox is configured with CONFIG_FEATURE_FANCY_ECHO enabled (which
is the default in the OE Busybox defconfig) therefore leave as-is.
Signed-off-by: Andre McCurdy <armccurdy@gmail.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
