anaconda: auto-remove rootpw lines

Replace that lines with:
<auto-removed line containing rootpw>

in the following files:
 - backtrace
 - ks.cfg

Related to #1041558

Signed-off-by: Jakub Filak <jfilak@redhat.com>
wizard: put rootpw on the forbidden words list

Related to #1041558

Signed-off-by: Jakub Filak <jfilak@redhat.com>
problem_data: make ks.cfg file editable

Otherwise the GUI will not highlight the forbidden words in that file.

Related to #1041558

Signed-off-by: Jakub Filak <jfilak@redhat.com>