Call h5d_vlen_reclaim to release resource (#436)

Call h5d_vlen_reclaim to release resource

src/HDF5.jl

@@ -1368,15 +1368,16 @@ function read{S<:String}(obj::DatasetOrAttribute, ::Type{Array{S}})
         close(objtype)
     end
     if isempty(sz)
-        ret = S[]
+        h5t_close(memtype_id)
+        return S[]
     else
+        dspace = dataspace(obj)
         ret = Array{S}(sz)
         if isvar
             # Variable-length
             buf = Vector{Cstring}(len)
             h5t_set_size(memtype_id, H5T_VARIABLE)
             readarray(obj, memtype_id, buf)
-            # FIXME? Who owns the memory for each string? Julia v0.6+ won't free it.
             for i = 1:len
                 ret[i] = unsafe_string(buf[i])
             end
@@ -1395,9 +1396,14 @@ function read{S<:String}(obj::DatasetOrAttribute, ::Type{Array{S}})
                 src += ilen
             end
         end
+    try
+        h5d_vlen_reclaim(memtype_id, dspace.id, H5P_DEFAULT, buf)
+    finally
+        close(dspace)
+        h5t_close(memtype_id)
+    end
+        return ret
     end
-    h5t_close(memtype_id)
-    ret
 end
 read{S<:CharType}(obj::DatasetOrAttribute, ::Type{Array{S}}) = read(obj, Array{stringtype(S)})
 # Empty Array of strings