integral::evalf(): don't attempt to ignore problems.

integral::evalf(): don't attempt to ignore problems.

Don't ignore exceptions thrown by numerical integration routine.
In general, the code like this

try {
	// blah-blah
} catch (std::exception& err) { }

is just plain evil. Case in the point:

fsolve((1/(sqrt(2*Pi)))*integral(t,0,x,exp(-1/2*t^2))==0.5,x,0,100)
(cherry picked from commit 515171f0bcd42099c266713c3d605cd92cedd2e2)