fix tests

Author: JarettBakerDunn

source/particle/distribution.cc

@@ -485,7 +485,7 @@ namespace aspect
         }
       else
         {
-          Assert(false, ExcMessage("Unknown kernel function used in insert_kernel_sum_into_pdf."));
+          Assert(false, ExcMessage("Unknown kernel function used in apply_selected_kernel_function."));
           return 0.0;
         }
     }

tests/particle_histogram_addition_singlecell.prm

@@ -114,16 +114,16 @@ end
 
 subsection Particles
   set Particle generator name = ascii file
+  set Minimum particles per cell = 8
+  set Load balancing strategy = add particles
+  set Particle addition algorithm = histogram
+  set Addition histogram granularity = 8
   subsection Generator
     subsection Ascii file
-        set Data directory = ../../data/particle/generator/ascii/
+        set Data directory = ../data/particle/generator/ascii/
         set Data file name = particle_addition_test.dat
     end
   end
-  set Minimum particles per cell = 8
-  set Addition granularity = 5
-  set Load balancing strategy = add particles
-  set Particle addition algorithm = histogram
 end