Toolbox is definitely used from install_recovery. Addresses
the following denials:

  type=1400 audit(0.0:7): avc: granted { execute } for comm="install-recover" name="toolbox" dev="mmcblk0p41" ino=463 scontext=u:r:install_recovery:s0 tcontext=u:object_r:toolbox_exec:s0 tclass=file
  type=1400 audit(0.0:6): avc: granted { getattr } for comm="install-recover" path="/system/bin/toolbox" dev="mmcblk0p41" ino=463 scontext=u:r:install_recovery:s0 tcontext=u:object_r:toolbox_exec:s0 tclass=file
  type=1400 audit(0.0:13): avc: granted { read } for comm="log" path="/system/bin/toolbox" dev="mmcblk0p41" ino=463 scontext=u:r:install_recovery:s0 tcontext=u:object_r:toolbox_exec:s0 tclass=file
  type=1400 audit(0.0:9): avc: granted { read open } for comm="install-recover" path="/system/bin/toolbox" dev="mmcblk0p41" ino=463 scontext=u:r:install_recovery:s0 tcontext=u:object_r:toolbox_exec:s0 tclass=file

Change-Id: I51d6e474f34afe1f33ea8294a344aa71e41deead