[FIX][report_xls] Protect import. (#64)
[FIX][report_xls] Protect import. (#64)

[FIX][report_xls] Protect import.

Even after merging 2bf93a1d49f7c79062ab7c237ceb794cdbdec983, import still breaks when trying to use module's stuff at class definition time when module is not imported.

I move xsl types to a failure-safe scope.
syci/reporting-engine,open-synergy/reporting-engine,brain-tec/reporting-engine,ddico/reporting-engine,brain-tec/reporting-engine,eezee-it/reporting-engine,eezee-it/reporting-engine,open-synergy/reporting-engine,acsone/reporting-engine,open-synergy/reporting-engine,ddico/reporting-engine,eezee-it/reporting-engine,brain-tec/reporting-engine,acsone/reporting-engine,diagramsoftware/reporting-engine,ddico/reporting-engine,acsone/reporting-engine,diagramsoftware/reporting-engine,eezee-it/reporting-engine,diagramsoftware/reporting-engine,syci/reporting-engine,diagramsoftware/reporting-engine,brain-tec/reporting-engine,acsone/reporting-engine,ddico/reporting-engine,open-synergy/reporting-engine