Fix use of undefined session variable

Commit eb0f1b5 introduced uses of
variable session in lnt/server/reporting/summaryreport.py but one of
them is in function _build_data_table() which does not have a session
parameter. This commit adds the parameter and update call sites
accordingly, fixing one of Flake8's F821 warning (undefined name).

Reviewed By: tnfchris

Differential Revision: https://reviews.llvm.org/D94837

Author: Thomas Preud'homme

lnt/server/reporting/summaryreport.py

@@ -176,7 +176,7 @@ def should_be_in_report(machine):
         #   <machine id>)
 
         self.data_table = {}
-        self._build_data_table()
+        self._build_data_table(session)
 
         # Compute indexed data table by applying the indexing functions.
         self._build_indexed_data_table()
@@ -187,7 +187,7 @@ def should_be_in_report(machine):
         # Build final organized data tables.
         self._build_final_data_tables()
 
-    def _build_data_table(self):
+    def _build_data_table(self, session):
         def get_nts_datapoints_for_sample(ts, sample):
             # Get the basic sample info.
             run_id = sample[0]