Update adlists.default

Remove 'securemecca.com` list, as they block other content, not just ads and malware.

Pi-hole is about ad-blocking and privacy, not about censoring content.
See :https://www.reddit.com/r/pihole/comments/45xuh8/slug/d00xg02

adlists.default

@@ -6,7 +6,6 @@ http://pgl.yoyo.org/adservers/serverlist.php?
 http://someonewhocares.org/hosts/hosts
 http://winhelp2002.mvps.org/hosts.txt
 http://mirror1.malwaredomains.com/files/justdomains
-http://securemecca.com/Downloads/hosts.txt
 https://hosts.neocities.org/
 http://sysctl.org/cameleon/hosts
 https://zeustracker.abuse.ch/blocklist.php?download=domainblocklist
@@ -14,4 +13,3 @@ https://s3.amazonaws.com/lists.disconnect.me/simple_tracking.txt
 https://s3.amazonaws.com/lists.disconnect.me/simple_ad.txt
 http://optimate.dl.sourceforge.net/project/adzhosts/HOSTS.txt
 https://raw.githubusercontent.com/quidsup/notrack/master/trackers.txt
-