Striping functionality

[Joel Andres Granados <jgranado redhat com>]

Relevant to bug 134638 and 223673:

Modified anaconda so the user could have some way of striping his lvs 
(It only works for graphical installations).  The patch changes more 
things than I would want to.  And more likely introduces more bugs to 
the code than it takes out.  But I think it might be a nice work around 
for the time being.  The files and diffs are in 
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=134638.
regards.