Replace "sha1sum" with "openssl sha1 -r"

"sha1sum" is part of GNU Coreutils, neither BIND 9 dependency nor POSIX.
Replace it with "openssl sha1 -r" as OpenSSL is BIND 9 dependency.

bin/tests/system/keyfromlabel/tests.sh

@@ -23,7 +23,7 @@ keygen() {
 	id="$4"
 
 	label="${id}-${zone}"
-	p11id=$(echo "${label}" | sha1sum - | awk '{print $1}')
+	p11id=$(echo "${label}" | openssl sha1 -r | awk '{print $1}')
 	pkcs11-tool --module $SOFTHSM2_MODULE --token-label "softhsm2-keyfromlabel" -l -k --key-type $type:$bits --label "${label}" --id "${p11id}" --pin $(cat $PWD/pin) > pkcs11-tool.out.$zone.$id || return 1
 }