launchpad: fix upload path

As of recently, launchpad rejects uploads that don't specify
their ppa name. This didn't affect nightlies because the ppa
name is explicit (sflphone-nightly), but did break stable releases
because we rely on the implicit default PPA name, "ppa".

Refs #51465

Change-Id: I1ae4f7f5e1de21960240a4a50a8896a4208c5ee5

tools/build-system/launchpad/dput.conf

@@ -8,14 +8,14 @@ allow_unsigned_uploads = 0
 [sflphone-saucy]
 fqdn = ppa.launchpad.net
 method = ftp
-incoming = ~savoirfairelinux/ubuntu/saucy
+incoming = ~savoirfairelinux/ppa/ubuntu/saucy
 login = anonymous
 allow_unsigned_uploads = 0
 
 [sflphone-trusty]
 fqdn = ppa.launchpad.net
 method = ftp
-incoming = ~savoirfairelinux/ubuntu/trusty
+incoming = ~savoirfairelinux/ppa/ubuntu/trusty
 login = anonymous
 allow_unsigned_uploads = 0