obexd: Add missing phonebook backends

This adds missing phonebook backends to EXTRA_DIST so they can be build
from tarballs.

Fixes: bluez#222

Makefile.obexd

@@ -42,6 +42,8 @@ obexd_builtin_sources += obexd/plugins/pbap.c \
 				obexd/plugins/vcard.h obexd/plugins/vcard.c \
 				obexd/plugins/phonebook.h \
 				obexd/plugins/phonebook-@PLUGIN_PHONEBOOK@.c
+EXTRA_DIST += obexd/plugins/phonebook-dummy.c obexd/plugins/phonebook-ebook.c \
+				obexd/plugins/phonebook-tracker.c
 
 obexd_builtin_modules += mas
 obexd_builtin_sources += obexd/plugins/mas.c obexd/src/map_ap.h \