fixed two occurences where O.regions was used instead of regions (probably remains of old versions) (#72)

Author: chmerdon

src/common_operators/bilinear_operator.jl

@@ -383,7 +383,7 @@ function build_assembler!(A::AbstractMatrix, O::BilinearOperator{Tv}, FE_test, F
         regions = O.parameters[:regions]
         visit_region = zeros(Bool, maximum(itemregions))
         if length(regions) > 0
-            visit_region[O.regions] = true
+            visit_region[regions] .= true
         else
             visit_region .= true
         end

src/common_operators/bilinear_operator_dg.jl

@@ -339,7 +339,7 @@ function build_assembler!(A, O::BilinearOperatorDG{Tv}, FE_test, FE_ansatz, FE_a
         regions = O.parameters[:regions]
         visit_region = zeros(Bool, maximum(itemregions))
         if length(regions) > 0
-            visit_region[O.regions] = true
+            visit_region[regions] .= true
         else
             visit_region .= true
         end