Refactor changelog check into a generic function

This allows calling it early in generic_pack and avoid doing expensive
operations before finding out the ChangeLog is not updated.

buildpkg.packaging.solaris

@@ -426,18 +426,10 @@ auto_rel()
 	-e "s;%%DEPENDENCIES%%;${deps};g" \
 	    ${rn} > "$relmetadir/${secname}.txt"
 
-    # Add a ChangeLog if it exists
-    if [ -r $metadir/ChangeLog ]; then
-        echo "auto_rel: Adding ChangeLog to relnotes"
-        # See if we can find an entry for this build otherwise complain
-        if [ -z "$(${__grep} ${version}-${pkgver}$ $metadir/ChangeLog)" ]; then
-            error $E_MISSING_CHGLOGV auto_rel
-        fi
-        echo >> "$relmetadir/${secname}.txt"
-        cat $metadir/ChangeLog >> "$relmetadir/${secname}.txt"
-    else
-        error $E_MISSING_CHGLOG auto_rel
-    fi
+    # Add a ChangeLog
+    echo "auto_rel: Adding ChangeLog to relnotes"
+    echo >> "$relmetadir/${secname}.txt"
+    cat $metadir/ChangeLog >> "$relmetadir/${secname}.txt"
 
     ### Add the relnotes to the prototype file
     add_dir $defaultperms $defaultuid $defaultgid "${metaprefix}relnotes" $secname
@@ -952,6 +944,11 @@ generic_pack()
     if [ "$1" == "shortroot" ]; then
 	error $E_ARG_OBSO generic_pack
     fi
+
+    # Before doing any expensive operations
+    # check that the ChangeLog is in order
+    check_changelog
+
     clean meta
     if [ -d "${stagedir}${topinstalldir}${dir_prefix}/${_mandir}" ]; then
 	setdir ${stagedir}${topinstalldir}${dir_prefix}/${_mandir}