In NULL/READY, we should be able to switch profiles on encodebin,
this patch makes it tear down old profiles when new ones are set
if in NULL/READY states
https://bugzilla.gnome.org/show_bug.cgi?id=644416
with i686-apple-darwin10-gcc-4.2.1:
encoding-profile.h:134: warning: type qualifiers ignored on function return type
encoding-profile.c:240: warning: type qualifiers ignored on function return type
gstencodebin.c: In function 'next_unused_stream_profile':
gstencodebin.c:454: warning: format '%d' expects type 'int', but argument 8 has type 'GType'
gstencodebin.c:464: warning: format '%d' expects type 'int', but argument 8 has type 'GType'
