package/busybox: drop empty configure command

package/busybox: drop empty configure command

Since commit 50dc350c65 (package/busybox: update to 1.29.0), we no
longer define the BUSYBOX_NOCLOBBER_INSTALL macro, so it expands to an
empty string, so we end up with no action in BUSYBOX_CONFIGURE_CMDS.

Drop BUSYBOX_CONFIGURE_CMDS now that it serves no purpose.

Signed-off-by: Yann MORIN <yann.morin@orange.com>
Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Adam Duskett <aduskett@gmail.com>
Cc: Carlos Santos <casantos@datacom.com.br>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>