fix the travis python3.5 build issue

Author: vera121

scripts/build_win.cmd

@@ -46,27 +46,31 @@ if DEFINED APPVEYOR (
     :: Add the required channels
     conda config --add channels conda-forge
     conda config --add channels willyd
-    :: Update conda
-    REM conda update conda -y
-    :: avoid python automatically upgrade to higher version
-    conda config --set auto_update_conda False
-    :: Download other required packages
-    if !PYTHON_VERSION! EQU 2 (
-        conda install --yes cmake ninja numpy scipy protobuf==3.1.0 six scikit-image pyyaml pydotplus graphviz
-    )
-    if !PYTHON_VERSION! EQU 2.7 (
-        conda install --yes cmake ninja numpy scipy protobuf==3.1.0 six scikit-image pyyaml pydotplus graphviz
-    )
-    if !PYTHON_VERSION! EQU 3 (
-        conda install --yes cmake ninja numpy scipy protobuf==3.1.0 six scikit-image pyyaml pydotplus graphviz
-    )
-    if !PYTHON_VERSION! EQU 3.5 (
-        conda install --yes cmake ninja numpy scipy protobuf==3.1.0 six scikit-image pyyaml pydotplus graphviz
-        pip install six
-    )
+
     if !PYTHON_VERSION! EQU 3.6 (
+        :: avoid conda automatically updating python to higher version
+        conda config --set auto_update_conda False
         conda install --yes cmake ninja numpy scipy protobuf==3.7.1 six scikit-image pyyaml pydotplus graphviz
     )
+    else (
+        :: Update conda
+        conda update conda -y
+
+        :: Download other required packages
+        if !PYTHON_VERSION! EQU 2 (
+            conda install --yes cmake ninja numpy scipy protobuf==3.1.0 six scikit-image pyyaml pydotplus graphviz
+        )
+        if !PYTHON_VERSION! EQU 2.7 (
+            conda install --yes cmake ninja numpy scipy protobuf==3.1.0 six scikit-image pyyaml pydotplus graphviz
+        )
+        if !PYTHON_VERSION! EQU 3 (
+            conda install --yes cmake ninja numpy scipy protobuf==3.1.0 six scikit-image pyyaml pydotplus graphviz
+        )
+        if !PYTHON_VERSION! EQU 3.5 (
+            conda install --yes cmake ninja numpy scipy protobuf==3.1.0 six scikit-image pyyaml pydotplus graphviz
+            pip install six
+        )
+    )
 
     if ERRORLEVEL 1  (
       echo ERROR: Conda update or install failed