docs/manual: fix packages having a subdirectory

efl and matchbox no longer have a subdirectory containing multiple
packages, so they are no longer good examples of that. Mention qt5 and
gstreamer instead.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

docs/manual/adding-packages-directory.txt

@@ -7,7 +7,7 @@ First of all, create a directory under the +package+ directory for
 your software, for example +libfoo+.
 
 Some packages have been grouped by topic in a sub-directory:
-+x11r7+, +efl+ and +matchbox+. If your package fits in
++x11r7+, +qt5+ and +gstreamer+. If your package fits in
 one of these categories, then create your package directory in these.
 New subdirectories are discouraged, however.