rename disableStateSync to isStateSyncDisabled
rename disableStateSync to isStateSyncDisabled

Summary: as title

Reviewed By: aeckert

Differential Revision: D5149205

fbshipit-source-id: 5e411269ba37d21ec04d3a97500965848c0193c2

peterlei/fboss,peterlei/fboss,peterlei/fboss,peterlei/fboss