package/busybox: fix individual binaries installation

Call BUSYBOX_INSTALL_INDIVIDUAL_BINARIES in BUSYBOX_INSTALL_TARGET_CMDS,
not in BUSYBOX_INSTALL_INIT_SYSV. This should have been done in commit
b1e07d6d but was somehow lost during the
review/aply process.

Signed-off-by: Carlos Santos <unixmania@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>