Use -t devpts for /dev/pts mounts

Currently a bind is used when mounting /dev/pts in chroot.
This leads to problems - especially when running DIB in parallel:
It was observed that the /dev/pts mount vanishes from the host
system.

This patch uses '-t devpts' - as it is done for /sys and /proc -
for handling /dev/pts.

Change-Id: Id7775ae6fca6502af800e7b73a00862ef320206b
Signed-off-by: Andreas Florath <andreas@florath.net>

diskimage_builder/elements/yum-minimal/root.d/08-yum-chroot

@@ -223,7 +223,7 @@ function _install_pkg_manager {
 sudo mkdir -p $TARGET_ROOT/proc $TARGET_ROOT/dev $TARGET_ROOT/sys
 sudo mount -t proc none $TARGET_ROOT/proc
 sudo mount --bind /dev $TARGET_ROOT/dev
-sudo mount --bind /dev/pts $TARGET_ROOT/dev/pts
+sudo mount -t devpts /dev/pts $TARGET_ROOT/dev/pts
 sudo mount -t sysfs none $TARGET_ROOT/sys
 
 # initalize rpmdb

diskimage_builder/elements/zypper-minimal/root.d/08-zypper-chroot

@@ -87,7 +87,7 @@ sudo zypper ${ZYPPER_TARGET_OPTS} refresh
 sudo mkdir -p $TARGET_ROOT/proc $TARGET_ROOT/dev $TARGET_ROOT/sys
 sudo mount -t proc none $TARGET_ROOT/proc
 sudo mount --bind /dev $TARGET_ROOT/dev
-sudo mount --bind /dev/pts $TARGET_ROOT/dev/pts
+sudo mount -t devpts /dev/pts $TARGET_ROOT/dev/pts
 sudo mount -t sysfs none $TARGET_ROOT/sys
 
 # Install filesystem, base and useful tools

diskimage_builder/lib/common-functions

@@ -316,7 +316,7 @@ function mount_proc_dev_sys () {
     # supporting kernel file systems
     sudo mount -t proc none $TMP_MOUNT_PATH/proc
     sudo mount --bind /dev $TMP_MOUNT_PATH/dev
-    sudo mount --bind /dev/pts $TMP_MOUNT_PATH/dev/pts
+    sudo mount -t devpts /dev/pts $TMP_MOUNT_PATH/dev/pts
     sudo mount -t sysfs none $TMP_MOUNT_PATH/sys
 }