DAM active_stage is stored in restart file for spin-up simulations

[tanzeli1982]

As described, if using the restart file from spin-up simulations, the active_stage of dams could always be 2 in simulations even if the dams have not been built.

[tanzeli1982]

These four variables in the restart file are affected.

double DAM_STORAGE_LIQ(rtmlat, rtmlon) ;
DAM_STORAGE_LIQ:long_name = "dam storage" ;
DAM_STORAGE_LIQ:units = "m3" ;
double DAM_RELEASE_LIQ(rtmlat, rtmlon) ;
DAM_RELEASE_LIQ:long_name = "dam release" ;
DAM_RELEASE_LIQ:units = "m3" ;
double DAM_STORMTHSTOP_LIQ(rtmlat, rtmlon) ;
DAM_STORMTHSTOP_LIQ:long_name = "dam StorMthStOp" ;
DAM_STORMTHSTOP_LIQ:units = "m3" ;
int DAM_ACTIVE_LIQ(rtmlat, rtmlon) ;
DAM_ACTIVE_LIQ:long_name = "dam active stage" ;
DAM_ACTIVE_LIQ:units = "no unit" ;