start_new_disc: fix a quoting bug

That bug led to a failure when CODENAME is kali-last-snapshot.

debian/changelog

@@ -19,6 +19,10 @@ debian-cd (3.1.28) UNRELEASED; urgency=medium
   * Add missing export keyword for ARCHIVE_KEYRING_FILE and
     ARCHIVE_KEYRING_PACKAGE variables in CONF.sh.
 
+  [ Raphaël Hertzog ]
+  * Fix a quoting bug that leads to failure in start_new_disc
+    when CODENAME is kali-last-snapshot.
+
  -- Holger Levsen <holger@debian.org>  Wed, 23 Oct 2019 18:06:41 +0200
 
 debian-cd (3.1.27) unstable; urgency=medium

tools/start_new_disc

@@ -22,7 +22,7 @@ CDDIR=$BDIR/CD${DISKNUM}
 DATE=`cat $BDIR/DATE`
 DI_DATA_DIR=$BASEDIR/data/$DI_CODENAME
 
-CAPCODENAME=`perl -e "print ucfirst("$CODENAME")"`
+CAPCODENAME=`perl -e "print ucfirst('$CODENAME')"`
 
 NUM_ARCHES=`echo $ARCHES | wc -w`
 case "$ARCHES" in