[LNT] Python 3 support: store color value as int

[thopre]

Summary

Page v4_graph.html sets the background color of some table entries from
float color values set in the v4_graph() method of lnt.server.ui.views
module using the %x specifier. However Python 3 gives an error in such a
case because it only accepts integer values. Under Python 2 an implicit
cast to int was performed. This commit adds an explicit cast to int when
storing the color value to satisfy the Python 3 requirement for %x
format specifier.

[thopre]

Committed as de6c3f84b9bde2cd9a882256e2bfd6e97e51f014

lnt/server/ui/views.py

def v4_graph():
     overview_plots = []
     baseline_plots = []
     revision_cache = {}
     num_plots = len(graph_parameters)
     for i, (machine, test, field, field_index) in enumerate(graph_parameters):
         # Determine the base plot color.
         col = list(util.makeDarkColor(float(i) / num_plots))
         url = "/".join([str(machine.id), str(test.id), str(field_index)])
-        legend.append(LegendItem(machine, test.name, field.name, tuple(col),
-                                 url))
+        legend.append(LegendItem(machine, test.name, field.name,
+                                 tuple(map(int, col)), url))
 
         # Load all the field values for this test on the same machine.
         #
         # FIXME: Don't join to Order here, aggregate this across all the tests
         # we want to load. Actually, we should just make this a single query.
         #
         # FIXME: Don't hard code field name.
         q = session.query(field.column, ts.Order.llvm_project_revision,
for i, (machine, test, field, field_index) in enumerate(graph_parameters):
             # Skip this baseline if there is no data.
             if not samples:
                 continue
             mean = sum(samples)/len(samples)
             # Darken the baseline color distinguish from non-baselines.
             # Make a color closer to the sample than its neighbour.
             color_offset = float(baseline_id) / num_baselines / 2
             my_color = (i + color_offset) / num_plots
-            dark_col = list(util.makeDarkerColor(my_color))
+            dark_col = list(map(int, util.makeDarkerColor(my_color)))
             str_dark_col = util.toColorString(dark_col)
             baseline_plots.append({
                 'color': str_dark_col,
                 'lineWidth': 2,
                 'yaxis': {'from': mean, 'to': mean},
                 'name': q_baseline[0].llvm_project_revision,
             })
             baseline_name = ("Baseline {} on {}"