we don't need unless check because the CAS will return false if a Tan…

…kard::Client has already been set

lib/tankard.rb

@@ -14,7 +14,7 @@ class << self
     include Configuration
 
     def client
-      @client.compare_and_swap(nil, Tankard::Client.new(credentials)) unless @client.value
+      @client.compare_and_swap(nil, Tankard::Client.new(credentials))
       @client.value
     end