Fix quality conversion factor error in ENsetqualtype

Reported here:

http://community.wateranalytics.org/t/difference-in-water-age-calculated-in-epanet-and-in-matlab-using-epanet-matlab-toolkit/406/12

src/epanet.c

@@ -2310,6 +2310,7 @@ int  DLLEXPORT ENsetqualtype(int qualcode, char *chemname, char *chemunits, char
    if (!Openflag) return(102);
    if (qualcode < EN_NONE || qualcode > EN_TRACE) return(251);
    Qualflag = (char)qualcode;
+   Ctol *= Ucf[QUALITY];
    if (Qualflag == CHEM)                   /* Chemical constituent */
    {
       strncpy(ChemName,chemname,MAXID);
@@ -2355,6 +2356,8 @@ int  DLLEXPORT ENsetqualtype(int qualcode, char *chemname, char *chemunits, char
    Ucf[LINKQUAL]  = ccf;
    Ucf[REACTRATE] = ccf;
 
+   Ctol /= Ucf[QUALITY];
+
    return(0);
 }