obexd: Fix segfault in parse_filter_read and parse_filter_priority

obexd: Fix segfault in parse_filter_read and parse_filter_priority

Calls to ListMessages with filter 'Read' or 'Priority' caused a segfault
in parse_filter_read / parse_filter_priority. The functions read
D-Bus boolean values (uint32) into uint8.

0  0x00007ffff730332d in ?? () from /usr/lib/libdbus-1.so.3
1  0x00007ffff7304219 in dbus_message_iter_next () from /usr/lib/libdbus-1.so.3
2  0x000000000043ef0f in parse_message_filters (
    apparam=<error reading variable: Cannot access memory at address 0x7ffffeffff08>,
    iter=<error reading variable: Cannot access memory at address 0x7ffffeffff00>)
    at obexd/client/map.c:1246