Added CIRCUIT_PURPOSE_S_HSDIR_POST to connection_ap_expire_beggining()
"circuit->purpose == CIRCUIT_PURPOSE_C_GENERAL" if statement as we added
special circuit purposes for fetching/uploading HS descs in #13837.

Fixes #24947.

Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>