Bug fix in FindPointsGSLIB::Interpolate with L2_FECollection in parallel
Bug fix in FindPointsGSLIB::Interpolate with L2_FECollection in parallel

Previously if a given MPI task did not find any local points with
gsl_code==1 (indicating a boundary), that task would exit
FindPointsGSLIB::Interpolate before tasks that found boundary points.
This could lead to the program hanging due to subsequent communication
calls.  To avoid this behavior, we only return early if no MPI task
found any boundary points.

mfem/mfem,mfem/mfem,mfem/mfem,mfem/mfem,mfem/mfem