Fix "post-redirect" not working when one of the parameters is named "submit".
Fix "post-redirect" not working when one of the parameters is named "submit".

It appears that there is some special processing of elements named "submit"
when triggering form-submit through javascript. This patch adds a workaround
for that.

Thanks to Christian Gijtenbeek for finding and fixing this bug!

rchavik/simplesamlphp,rchavik/simplesamlphp,rchavik/simplesamlphp,rchavik/simplesamlphp