This update for prosody fixes the following issues:

- Update to 0.9.13 (boo#1093088):
Security:
* Fix for compatibility with LuaSocket 3.0rc1 (fixes denial of service from remote)
* mod_register: Require encryption before registration if c2s_require_encryption is set (fixes #595[1])
* MUC: Ensure that elements which match our from are stripped (fixes #1055[2])
Fixes and improvements:
* Compatibility fix with newer LuaSec 0.6 (fixes #781[3])
* mod_presence: Send probe once subscribed (fixes #794[4])
* mod_net_multiplex: Enable SSL on the SSL port (fixes #803[5])
Minor changes:
* core.rostermanager: Add method for checking if the user is subscribed to a contact
* mod_saslauth: Log SASL failure reason
* mod_disco: Correctly set the 'node' attr (fixes #449)
* mod_bosh: Update session.conn to point to the current connection (fixes #890)
* net.dns: Simplify expiry calculation (fixes #919)
* mod_watchregistrations: Return the pointer to the root of the stanza, fixes #922.
* mod_disco: Add an account/registered identity on subscribed accounts, fixes #826.
* mod_welcome: Return the pointer to the root of the stanza, fixes a bug similar to #922.
* net.dns: Prevent answers from immediately expiring even if TTL=0 (see #919)
* mod_saslauth: Use correct varible name (thanks Roi)
* mod_c2s: Iterate over child tags instead of child nodes in stream error (fixes traceback from #987)
* mod_component, mod_s2s: Iterate over child tags instead of child nodes (can include text)
in stream error (same as 176b7f4e4ac9)
* MUC: Always send subject message, even if it is empty (fixes #1053)
* MUC: fix the @from on in history replay (fixes #1054)
* MUC: Rename variable to make it clearer that it is the room JID and not the MUC host