build: Make sure --target-glib used with Vala is the correct GLib version

Was set to 2.34, now we use ${GLIB_REQUIRED} in configure.

This avoids a bunch of deprecation warnings about g_type_init() (fixed in
2.36) and since we depend on ${GLIB_REQUIRED} it's fine if earlier versions
break with Vala built C.
tracker-needle: Fixed typo in Makefile.am, VALACFLAGS was not being used

Fixes --target-glib=${GLIB_VERSION} not being used among other things
tracker-needle: Fixed GTK+ 3.0 deprecations.

Remaining cases are from generated C that Vala needs to fix (e.g.
gtk_icon_info_free(), etc).