cksum: Refine schema cksum validation

Calculates the cksum removing the cksum line using a more
strict regex than the used previously.
It fixes a problem when calculating the cksum of a schema that
has fields with the substring cksum (e.g.: a checksum column),
lines that the previous cksum calculation incorrectly removes
before running cksum.
Also, the tool calculate-schema-cksum is introduced. This tool
calculates the cksum of a schema file. It could be used in other
programs, instead of calculating the cksum in an eventually
different way than the expected by cksum-schema-check and other
tools.

Signed-off-by: Esteban Rodriguez Betancourt <estebarb@hpe.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

Makefile.am

@@ -107,6 +107,7 @@ EXTRA_DIST = \
 	boot.sh \
 	build-aux/cccl \
 	build-aux/cksum-schema-check \
+	build-aux/calculate-schema-cksum \
 	build-aux/dist-docs \
 	build-aux/sodepends.pl \
 	build-aux/soexpand.pl \

build-aux/calculate-schema-cksum

@@ -0,0 +1,4 @@
+#!/bin/sh
+
+schema=$1
+sed '/"cksum": *"[0-9][0-9]* [0-9][0-9]*",/d' $schema | cksum

build-aux/cksum-schema-check

@@ -3,7 +3,8 @@
 schema=$1
 stamp=$2
 
-sum=`sed '/cksum/d' $schema | cksum`
+cksumcheckpath=`dirname $0`
+sum=`$cksumcheckpath/calculate-schema-cksum $schema`
 expected=`sed -n 's/.*"cksum": "\(.*\)".*/\1/p' $schema`
 if test "X$sum" = "X$expected"; then
     touch $stamp