Change format of backtrace to one without varibles.
Change format of backtrace to one without varibles.

This patch changes the backtrace format user when logging an error
to a format which doesn't include the variables passed to functions
in the output. This is done to avoid disclosing the password of the
user.


Rud5G/simplesamlphp,Rud5G/simplesamlphp,Rud5G/simplesamlphp,Rud5G/simplesamlphp