package/refpolicy: fix build with samba

Fix the following build failure with samba raised since commit
49f6b2f3:

 Compiling targeted policy.31
 env LD_LIBRARY_PATH="/tmp/instance-5/output-1/host/lib:/tmp/instance-5/output-1/host/usr/lib" /tmp/instance-5/output-1/host/usr/bin/checkpolicy -c 31 -U deny -S -O -E policy.conf -o policy.31
 policy/modules/services/samba.te:399:ERROR 'type crack_db_t is not within scope' at token ';' on line 360232:
 	allow smbd_t crack_db_t:dir { getattr search open };
 #line 399
 checkpolicy:  error(s) encountered while parsing configuration

Fixes:
 - http://autobuild.buildroot.org/results/ab7098948d1920e42fa587e07f0513f23ba7fc74



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>