runqemu-export-rootfs and friends: don't put pseudo db in target fs

runqemu-export-rootfs and friends: don't put pseudo db in target fs

In a few places, we have scripts which use <rootfs>/var/pseudo for
the pseudo state directory controlling a given filesystem. This
seems possibly risky because it means that stuff running under
qemu or whatnot could wipe out the data being used to handle that
rootfs. Move this to:
  <rootfs>/../$(basename_rootfs).pseudo_state
to avoid problems.

This also solves at least one case (not directly hit by yocto's
tree) wherein you could end up trying to remove a rootfs while
pseudo was using a database inside that rootfs, and thus the
remove would fail.

(From OE-Core rev: aa5d6bd006d3b4eede21d8987451876ed3385ab8)

Signed-off-by: Peter Seebach <peter.seebach@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>