Fix prompt with umv

Sounds like the umv function breaks the layout if used with tools from prompt toolkit.

This can be seen during the focusing procedure of the KB.

This patch is a work around but probably, a better thing have to be found.

Test

from bliss.shell import getval
umv(roby, 10000); getval.title("ABCDEFGHIJKLMNOPQRSTUVWXYZ")

Without the patch

The result depends on the timing

       roby  


user    0.000
dial    10000.000RSTUVWXYZ

       roby  

user    10000.000
dial    10000.000
ABCDEFGHIJKLMNOPQRSTUVWXYZ

With the patch

The result is always the same.

       roby  
user 10000.000
dial 10000.000


ABCDEFGHIJKLMNOPQRSTUVWXYZ