Removes check of potentially uninitialized values on resize.

hormaxed and vertmaxed may not be set when a window is resized, in any
case it seems as if they ought to be set to false regardless of their
initial value following a resize operation.

This generates a valgrind warning on window resize events and looks like
this:
==25842== Conditional jump or move depends on uninitialised value(s)
==25842==    at 0x403AA7: mouseresize (2bwm.c:1169)
==25842==    by 0x4048AE: mousemotion (2bwm.c:1707)
==25842==    by 0x4030E8: buttonpress (2bwm.c:1736)
==25842==    by 0x402F1E: main (2bwm.c:1837)
==25842==