modify VENUS cloud mask gipp params to come back to the ones used in VM1

VENUS/VE_TEST_GIP_L2COMM_L_ALLSITES_00001_20170801_21000101.EEF

@@ -216,13 +216,13 @@
       <!-- Threshold on surface reflectance in the Refl_water_band band for pixels declared water (if sunglint_flag is True) -->
       <Water_Sunglint_Reflectance_Threshold>0.16</Water_Sunglint_Reflectance_Threshold>
       <!-- Minimum Threshold on surface reflectance variation with time in the blue band -->
-      <Min_Threshold_Var_Blue>0.016</Min_Threshold_Var_Blue>
+      <Min_Threshold_Var_Blue>0.020</Min_Threshold_Var_Blue>
       <!-- Maximum Threshold on surface reflectance variation with time in the blue band -->
-      <Max_Threshold_Var_Blue>0.060</Max_Threshold_Var_Blue>
+      <Max_Threshold_Var_Blue>0.070</Max_Threshold_Var_Blue>
       <!-- Difference between the threshold used for the initial variation detection step and the one used for the extension step -->
-      <Delta_Threshold>0.003</Delta_Threshold>
+      <Delta_Threshold>0.005</Delta_Threshold>
       <!-- Time delay after which Refl_Variation_Threshold is doubled (in days) -->
-      <Cloud_Forgetting_Duration>45</Cloud_Forgetting_Duration>
+      <Cloud_Forgetting_Duration>30</Cloud_Forgetting_Duration>
       <!-- Default altitude attributed to cloud pixels, if stereoscopy has not detected any cloud (in meter) -->
       <Default_Altitude>500</Default_Altitude>
       <!-- Maximum cloud altitude, to find the zone where clouds outside the image could cast shadows (in meter) -->
@@ -236,7 +236,7 @@
       <!-- Parameter for comparison of variations in the blue and in the red -->
       <K_Red_Blue>1.50</K_Red_Blue>
       <!-- Radius of the correlation window -->
-      <N_Correl>3</N_Correl>
+      <N_Correl>8</N_Correl>
       <!-- Minimum number of pixels to take correlation into account -->
       <Min_Pixel_Correl>15</Min_Pixel_Correl>
       <!-- Minimum altitude excursion around the altitude obtained via stereoscopy, to refine the altitude value (in meter) -->