Generate an AKey if wp_salt is not long enough

git-svn-id: https://plugins.svn.wordpress.org/duo-wordpress/trunk@881134 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fixed curl proxy. Merge from @spacedmonkey

git-svn-id: https://plugins.svn.wordpress.org/duo-wordpress/trunk@881136 b8457f37-d9ea-0310-8a92-e5e31aec5664