Fixed AWS doc build deployment

.travis.yml

@@ -149,10 +149,10 @@ jobs:
       env: DESC="docs" CHANS_DEV="-c pyviz/label/dev -c bokeh/label/dev" HV_DOC_HTML='true' HV_DOC_GALLERY='false' HV_REQUIREMENTS="doc"
       script:
         - bokeh sampledata
+        - conda install -c conda-forge awscli
         - nbsite generate-rst --org pyviz --project-name holoviews --skip ^reference
         - nbsite build --what=html --output=builtdocs
       after_success:
-        - pip install awscli
         - aws s3 sync ./ s3://holoviews-doc-builds/$TRAVIS_BUILD_NUMBER --exclude=".git/*" --exclude="doc/nbpublisher/*"
 
     - &gallery_build