EVM hmac calculation

For debugging purpose it is nice to have evm hmac calculation for
labeling filesystem using hmac.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

tests/evm_hmac_all.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+verbose=""
+if [ "$1" = "-v" ] ; then
+	verbose="-v"
+	shift 1
+fi
+
+dir=${1:-/}
+
+echo "Label: $dir"
+
+find $dir \( -fstype rootfs -o -fstype ext3 -o -fstype ext4 \) -type f -uid 0 -exec evmctl hmac --imahash $verbose '{}' \;
+