Update URL for CLT download

http://connect.apple.com is still down, but
https://developer.apple.com/downloads has all of the Apple developer
downloads available.

Fixes Homebrew/homebrew#21812.

Library/Homebrew/blacklist.rb

@@ -37,7 +37,7 @@ def blacklisted? name
     "lzma is now part of the xz formula."
   when 'xcode' then <<-EOS.undent
     Xcode can be installed via the App Store (on Lion or newer), or from:
-      http://connect.apple.com/
+      https://developer.apple.com/downloads/
     EOS
   when 'gtest', 'googletest', 'google-test' then <<-EOS.undent
     Installing gtest system-wide is not recommended; it should be vendored

Library/Homebrew/cmd/doctor.rb

@@ -223,11 +223,13 @@ end
 def __check_clt_up_to_date
   if not MacOS::CLT.installed? then <<-EOS.undent
     No developer tools installed
-    You should install the Command Line Tools: http://connect.apple.com
+    You should install the Command Line Tools:
+      https://developer.apple.com/downloads/
     EOS
   elsif MacOS::CLT.outdated? then <<-EOS.undent
     A newer Command Line Tools release is available
-    You should install the latest version from: http://connect.apple.com
+    You should install the latest version from:
+      http://connect.apple.com
     EOS
   end
 end

Library/Homebrew/requirements.rb

@@ -60,7 +60,8 @@ class CLTDependency < Requirement
 
   def message; <<-EOS.undent
     The Command Line Tools are required to compile this software.
-    The standalone package can be obtained from http://connect.apple.com,
+    The standalone package can be obtained from
+    https://developer.apple.com/downloads/,
     or it can be installed via Xcode's preferences.
     EOS
   end