ima_evm_utils: Fix calculation of keyid for older distros

Older distros, such as Ubuntu Xenial or Centos 7, fail to calculate the
keyid properly in the bash script. Adding 'tail -n1' into the pipe fixes
the issue since we otherwise have two numbers in 'id' due to two
'BIT STRING's.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

tests/sign_verify.test

@@ -43,6 +43,7 @@ _keyid_from_cert() {
   id=$($cmd 2>/dev/null \
     | openssl asn1parse \
     | grep BIT.STRING \
+    | tail -n1 \
     | cut -d: -f1)
   if [ -z "$id" ]; then
     echo - "$cmd" >&2