Disable dhclient resolvconf enter hook

This is an expedient way to disable the resolvconf hook, which will run every time a DHCP lease is acquired/renewed [and thereby rewrite the resolver configuration]. Notice that the file is not deleted; only rendered inexecutable by means of compression.

This addresses the phenomenon observed when the set of nameservers received from the DHCP server on the primary interface differs from any other sets configured elsewhere, thereby occluding others in the generated resolv.conf. Specifically, this has been observed when the primary interface is initially configured through DHCP and subsequently modified to a static configuration. 

Essentially, the approach is intended to prefer static nameserver configurations over dynamic updates [triggered by DHCP lease renewals].