Fix typo, thanks!

modules/exploits/linux/samba/is_known_pipename.rb

@@ -139,7 +139,7 @@ class MetasploitModule < Msf::Exploit::Remote
     end
   end
 
-  # Detemrine whether a directory in a share is writeable
+  # Determine whether a directory in a share is writeable
   def verify_writeable_directory(share, directory="")
     begin
       simple.connect("\\\\#{rhost}\\#{share}")