important fix for backward compatibility to 1.2

a grave bug has been affecting 1.3 and 1.3.1 releases, which makes keys
created with those versions incompatible with other Tomb versions.
This bug is now fixed and Tomb should be able again to open old tombs.
A script to sanitize keys will be released soon.

tomb

@@ -605,7 +605,11 @@ change_passwd() {
     drop_key
 
     {
-	gen_key $lukskey > ${tmpnewkey}
+
+	local algo
+	{ option_is_set -o } && { algopt="`option_value -o`" }
+
+	gen_key $lukskey $algopt > ${tmpnewkey}
 
 	if ! is_valid_key $tmpnewkey; then
 	    die "Error: the newly generated keyfile does not seem valid"
@@ -718,7 +722,7 @@ get_lukskey() {
 	    -d "${keyfile}" 2> $res
 
 	unset tombpass
-	grep 'DECRYPTION_OKAY' $res
+	grep 'DECRYPTION_OKAY' $res > /dev/null
 	ret=$?; rm -f $res
 
     fi
@@ -733,7 +737,7 @@ gen_key() {
 # $1 the lukskey to encrypt
 # $2 is the --cipher-algo to use (string taken by GnuPG)
     local lukskey="$1"
-    local algo="$2"
+    local algo="${2:-AES256}"
     # here user is prompted for key password
     local tombpass=""
     local tombpasstmp=""