Refactor OptAddressLocal logic

@bcoles +1

lib/msf/core/opt_address_local.rb

@@ -15,21 +15,19 @@ class OptAddressLocal < OptAddress
 
   def normalize(value)
     return unless value.kind_of?(String)
+    return value unless interfaces.include?(value)
 
-    if interfaces.include?(value)
-      ip_address = NetworkInterface.addresses(value).values.flatten.map{|x| x['addr']}.select do |addr|
-        begin
-          IPAddr.new(addr).ipv4?
-        rescue IPAddr::InvalidAddressError
-          nil
-        end
+    ip_address = NetworkInterface.addresses(value).values.flatten.map{|x| x['addr']}.select do |addr|
+      begin
+        IPAddr.new(addr).ipv4?
+      rescue IPAddr::InvalidAddressError
+        nil
       end
-
-      return if ip_address.blank?
-      return ip_address.first
     end
 
-    value
+    return if ip_address.blank?
+
+    ip_address.first
   end
 
   def valid?(value, check_empty: true)