Check exploit stance for array as well as string

An exploit can be both aggressive and passive.

Author: wvu

lib/msf/core/exploit.rb

@@ -672,14 +672,14 @@ def stance
   # Returns true if the exploit has an aggressive stance.
   #
   def aggressive?
-    (stance == Stance::Aggressive)
+    stance.include?(Stance::Aggressive)
   end
 
   #
   # Returns if the exploit has a passive stance.
   #
   def passive?
-    (stance == Stance::Passive)
+    stance.include?(Stance::Passive)
   end
 
   #