oleaut32: Fixed time outputing for dates before 1899 in VarBstrFromDate.

dlls/oleaut32/tests/vartype.c

@@ -4951,6 +4951,7 @@ static void test_VarBstrFromDate(void)
   BSTR_DATE(365.25, "12/30/1900 6:00:00 AM");
   BSTR_DATE(1461.0, "12/31/1903");
   BSTR_DATE(1461.5, "12/31/1903 12:00:00 PM");
+  BSTR_DATE(-49192.24, "4/24/1765 5:45:36 AM");
   todo_wine { BSTR_DATE(-657434.0, "1/1/100"); }
   BSTR_DATE(2958465.0, "12/31/9999");
 

dlls/oleaut32/vartype.c

@@ -6619,7 +6619,7 @@ HRESULT WINAPI VarBstrFromDate(DATE dateIn, LCID lcid, ULONG dwFlags, BSTR* pbst
 
     if (whole == 0.0)
       dwFlags |= VAR_TIMEVALUEONLY;
-    else if (partial < 1e-12)
+    else if (partial > -1e-12 && partial < 1e-12)
       dwFlags |= VAR_DATEVALUEONLY;
   }