Improve handling missing coverage info

ref: fastlane-community#25

lib/danger_plugin.rb

@@ -61,16 +61,21 @@ def produce_report(*args)
       report_json = nil
       manager = Xcov::Manager.new(config)
 
-      if Xcov.config[:html_report] || Xcov.config[:markdown_report] || Xcov.config[:json_report]
-        # Parse .xccoverage and create local report
-        report_json = manager.run
-      else
-        # Parse .xccoverage
-        report_json = manager.parse_xccoverage
-      end
+      begin
+        if Xcov.config[:html_report] || Xcov.config[:markdown_report] || Xcov.config[:json_report]
+          # Parse .xccoverage and create local report
+          report_json = manager.run
+        else
+          # Parse .xccoverage
+          report_json = manager.parse_xccoverage
+        end
+
+        # Map and process report
+        process_report(Xcov::Report.map(report_json))
 
-      # Map and process report
-      process_report(Xcov::Report.map(report_json))
+      rescue => e
+        puts e
+      end
     end
 
     # Outputs a processed report with Danger