exception is caught. 

The parameter list was printed every time a parameter exception was
thrown in the parameter class. This made it impossible to catch
parameter exceptions without having a paramter list output every time.
Now it is printed only if the start function exits with a parameter
error.



git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@15229 2fb0f335-1f38-0410-981e-8018bf24f1b0