fix cert verification in delicious calls

fixes #6383

testplan: add delicious to your user profile in three cases:
 * /etc/ssl/certs doesn't exist
 * /etc/ssl/certs exists but doesn't include the root CA for https://api.del.icio.us
 * /etc/ssl/certs exist and includes the CA
 In the first and last cases, canvas should be able to request your delicious profile successfully. In the second case, it should fail.

Change-Id: If2f4e3f7b534bd05236e50f068472e2b7baf2c9c
Reviewed-on: https://gerrit.instructure.com/7033
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Zach Wily <zach@instructure.com>

lib/delicious_diigo.rb

@@ -22,13 +22,13 @@ module DeliciousDiigo
   require 'uri'
   
   def delicious_generate_request(url, method, user_name, password)
-    rootCA = 'etc/ssl/certs'
+    rootCA = '/etc/ssl/certs'
     
     url = URI.parse url
     http = Net::HTTP.new(url.host, url.port)
     http.use_ssl = (url.scheme == 'https')
-    if File.exist? rootCA
-      http.ca_file = rootCA
+    if File.directory? rootCA
+      http.ca_path = rootCA
       http.verify_mode = OpenSSL::SSL::VERIFY_PEER
       http.verify_depth = 5
     else
@@ -153,4 +153,4 @@ module DeliciousDiigo
         response.error!
     end
   end
-end
+end