Fix #6362, avoid overriding def peer repeatedly

def peer is a method that gets repeated a lot in modules, so we
should have it in the tcp mixin. This commit also clears a few
modules that use the HttpClient mixin with def peer.

modules/exploits/multi/misc/java_jdwp_debugger.rb

@@ -147,10 +147,6 @@ class Metasploit3 < Msf::Exploit::Remote
   end
 
 
-  def peer
-    "#{rhost}:#{rport}"
-  end
-
   def default_timeout
     datastore['RESPONSE_TIMEOUT']
   end