[ci] remove temp fix and fix activation for conda (#2280)

* removed temp fix for conda

* fixed conda activation before any conda command

.appveyor.yml

-version: 2.2.4.{build}
+version: 2.2.4.{build}
 
 image: Visual Studio 2015
 platform: x64
@@ -27,8 +27,9 @@ install:
       }
   - set PATH=%MINICONDA%;%MINICONDA%\Scripts;%PATH%
   - ps: $env:LGB_VER = (Get-Content VERSION.txt).trim()
+  - activate
   - conda config --set always_yes yes --set changeps1 no
-  - conda install -q -y conda=4.6.14  # temp fix, change to update later
+  - conda update -q -y conda
   - conda create -q -y -n test-env python=%PYTHON_VERSION% matplotlib numpy pandas psutil pytest python-graphviz scikit-learn scipy
   - activate test-env
   - set PATH=%CONDA_PREFIX%\Library\bin\graphviz;%PATH%  # temp graphviz hotfix

.ci/setup.sh

@@ -57,4 +57,4 @@ if [[ $TRAVIS == "true" ]] || [[ $OS_NAME == "macos" ]]; then
     sh conda.sh -b -p $CONDA
 fi
 conda config --set always_yes yes --set changeps1 no
-conda install -q -y conda=4.6.14  # temp fix, change to update later
+conda update -q -y conda

.vsts-ci.yml

@@ -127,8 +127,7 @@ jobs:
   - powershell: Write-Host "##vso[task.prependpath]$env:CONDA\Scripts"
     displayName: Enable conda
   - script: |
-      conda install -q -y conda=4.6.14
-      conda create -q -y -n %CONDA_ENV% python=%PYTHON_VERSION% matplotlib numpy pandas psutil pytest python-graphviz scikit-learn scipy
+      cmd /c "activate & conda config --set always_yes yes --set changeps1 no & conda update -q -y conda & conda create -q -y -n %CONDA_ENV% python=%PYTHON_VERSION% matplotlib numpy pandas psutil pytest python-graphviz scikit-learn scipy"
       cmd /c "activate %CONDA_ENV% & powershell -ExecutionPolicy Bypass -File %BUILD_SOURCESDIRECTORY%/.ci/test_windows.ps1"
     displayName: Test
   - task: PublishBuildArtifacts@1