Note that expintegral_shi(x) is a real function - see A&S or Wolfram Alpha.
gives about .125872409 as does mpmath.
This come from
So Maxima is, oddly, using a different branch for this function even though they cite
The Exponential Integral Shi(z) (A&S 5.2.3)
and http://people.math.sfu.ca/~cbm/aands/page_231.htm clearly makes this something that should be real.
See http://trac.sagemath.org/sage_trac/ticket/11143 where this was first noticed.