debian: libmenu-cache-bin in fact conflicts with libmenu-cache[12]

The executables provided by libmenu-cache-bin use the same resources
that executables provided by libmenu-cache1 or libmenu-cache2. That was
valid between libmenu-cache1 and libmenu-cache2 but fortunately it will
be no longer because libmenu-cache4 if it happens will work with non
conflicting libmenu-cache-bin that is common for any libmenu-cache*.