lmdb: fix handling of mdb cursor
lmdb: fix handling of mdb cursor

emacstheviking/lambdanative,emacstheviking/lambdanative,gale320/lambdanative,VincentToups/lambdanative,gale320/lambdanative,emacstheviking/lambdanative,emacstheviking/lambdanative,emacstheviking/lambdanative,VincentToups/lambdanative,gale320/lambdanative,gale320/lambdanative,VincentToups/lambdanative,VincentToups/lambdanative,gale320/lambdanative,VincentToups/lambdanative