test-client: initialize input instance.
test-client: initialize input instance.

In seat_handle_capabilities, if input->pointer is not properly
initialized, then it will contain an arbitrary value and results
in the wl_pointer listener not getting registered if that value
is not 0/null.  Thus, use calloc to initialize the "input" instance.

This fixes https://bugs.freedesktop.org/show_bug.cgi?id=49937

Signed-off-by: U. Artie Eoff <32aece0d55055227b44d04b7d0051cf3d04ee871@intel.com>

sir-murray/weston,xorgy/weston,udoprog/weston,Tarnyko/weston-xdg_surface_present,Fantu/compositor-spice,jonnylamb/weston,kwm81/weston,udoprog/weston,krezovic/weston,kwm81/weston,giucam/weston,sir-murray/weston,krezovic/weston,Fantu/compositor-spice,Gnurou/weston,giucam/weston,xorgy/weston,Gnurou/weston,Fantu/compositor-spice,eyolfson/weston,jonnylamb/weston,mchalupa/weston,Tarnyko/weston-xdg_surface_present,eyolfson/weston,mchalupa/weston