recompress conditional snap channel

.travis.yml

@@ -135,19 +135,10 @@ deploy:
       stage: build
   - provider: snap
     snap: dvc_*.snap
-    channel: stable
+    channel: $SNAP_CHANNEL
     skip_cleanup: true
     on:
-      condition: "$(./scripts/ci/deploy_condition.sh dvc_*.snap)"
-      tags: true
-      repo: iterative/dvc
-      stage: build
-  - provider: snap
-    snap: dvc_*.snap
-    channel: edge
-    skip_cleanup: true
-    on:
-      branch: master
-      condition: "$(./scripts/ci/deploy_condition.sh dvc_*.snap)"
+      all_branches: true
+      condition: "$(./scripts/ci/deploy_condition.sh dvc_*.snap) && ($TRAVIS_BRANCH = master || -n $TRAVIS_TAG)"
       repo: iterative/dvc
       stage: build

scripts/ci/before_install.sh

@@ -50,3 +50,9 @@ elif [[ "$TRAVIS_OS_NAME" == "osx" ]]; then
     ln -s -f /usr/local/bin/python3 /usr/local/bin/python
     ln -s -f /usr/local/bin/pip3 /usr/local/bin/pip
 fi
+
+if [[ -n "$TRAVIS_TAG" ]]; then
+    echo "export SNAP_CHANNEL=stable" >> env.sh
+else
+    echo "export SNAP_CHANNEL=edge" >> env.sh
+fi