travis: rebuild base-chroot via build.sh not prepare.sh.

common/travis/build.sh

@@ -6,6 +6,9 @@ if [ "$1" != "$2" ]; then
 	arch="-a $2"
 fi
 
+# Make sure `base-chroot` is really up-to-date
+/hostrepo/xbps-src -Ntf pkg base-chroot
+
 PKGS=$(/hostrepo/xbps-src sort-dependencies $(cat /tmp/templates))
 
 NPROCS=1

common/travis/prepare.sh

@@ -13,6 +13,3 @@ echo XBPS_ALLOW_CHROOT_BREAKOUT=yes >> etc/conf
 
 /bin/echo -e '\x1b[32mLinking / to /masterdir...\x1b[0m'
 ln -s / masterdir
-
-# Make sure `base-chroot` is really up-to-date
-/hostrepo/xbps-src -Ntf pkg base-chroot