Only do scenario smoothing if number of scenarios is explicitly positive

This helps in special cases where no. scenarios has been defined to some nonzero number
to allow moving the samples along with the dispatch. See changes to inc/3b_periodicLoop.gms in b6030656.

inc/3c_inputsLoop.gms

@@ -544,7 +544,7 @@ $offtext
 $ifthen.autocorr defined p_autocorrelation
 
 // Do smoothing
-if(mSettings(mSolve, 'scenarios'),  // Only do smooting if using long-term scenarios
+if(mSettings(mSolve, 'scenarios') > 0,  // Only do smooting if using long-term scenarios
     // Select the initial sample, the last time in it (t_)
     // and the forecast (f_) of the last simulated time step (t__) in it
     loop((ms_initial(mSolve, s_), t_, ft(f_, t__))