Fix #compatible? method

lib/msf/core/exploit/cmdstager.rb

@@ -163,6 +163,7 @@ module Exploit::CmdStager
   # Create an instance of the flavored stager.
   #
   # @return [Rex::Exploitation::CmdStagerBase] The cmd stager to use.
+  # @raise [NoMethodError] raised if the flavor doesn't exist.
   def create_stager
     STAGERS[flavor].new(exe)
   end
@@ -233,10 +234,11 @@ module Exploit::CmdStager
   #
   # @return [Array] the list of compatible cmd stager flavors.
   # @return [Symbol] the compatible cmd stager flavor.
+  # @return [String] the compatible cmd stager flavor.
   # @return [nil] if there isn't any compatible flavor defined.
   def target_flavor
-    return target.opts['CmdStagerFlavor'].to_sym if target && target.opts['CmdStagerFlavor']
-    return module_info['CmdStagerFlavor'].to_sym if module_info['CmdStagerFlavor']
+    return target.opts['CmdStagerFlavor'] if target && target.opts['CmdStagerFlavor']
+    return module_info['CmdStagerFlavor'] if module_info['CmdStagerFlavor']
     nil
   end
 
@@ -245,7 +247,16 @@ module Exploit::CmdStager
   # @param f [Symbol] The flavor to check
   # @returns  [Boolean] true if compatible, false otherwise.
   def compatible?(f)
-    target_flavor.nil? || target_flavor == f || target_flavor.include?(f)
+    return true if target_flavor.nil?
+    case target_flavor.class.to_s
+    when 'String'
+      return true if target_flavor == f.to_s
+    when 'Array'
+      target_flavor.each { |tr| return true if tr.to_sym == f }
+    when 'Symbol'
+      return true if target_flavor == f
+    end
+    false
   end
 
   # Code to execute before the cmd stager stub. This method is designed to be