ci: build kernel only when not a tag build

.travis.yml

@@ -17,22 +17,16 @@ env:
 matrix:
   include:
     - env: RELEASE=disco BUILD_DESKTOP=no BUILD_MINIMAL=no
-    - if: tag IS present
-      env: RELEASE=disco BUILD_DESKTOP=no BUILD_MINIMAL=yes
-    - if: tag IS present
-      env: RELEASE=disco BUILD_DESKTOP=yes BUILD_MINIMAL=no
-    - if: tag IS present
-      env: RELEASE=bionic BUILD_DESKTOP=no BUILD_MINIMAL=no
-    - if: tag IS present
-      env: RELEASE=bionic BUILD_DESKTOP=no BUILD_MINIMAL=yes
-    - if: tag IS present
-      env: RELEASE=bionic BUILD_DESKTOP=yes BUILD_MINIMAL=no
-    - if: tag IS present
-      env: RELEASE=buster BUILD_DESKTOP=no BUILD_MINIMAL=no
-    - if: tag IS present
-      env: RELEASE=buster BUILD_DESKTOP=no BUILD_MINIMAL=yes
-    - if: tag IS present
-      env: RELEASE=buster BUILD_DESKTOP=yes BUILD_MINIMAL=no
+    - env: RELEASE=bionic BUILD_DESKTOP=no BUILD_MINIMAL=no
+    - env: RELEASE=buster BUILD_DESKTOP=no BUILD_MINIMAL=no
+    # minimal build
+    - env: RELEASE=disco BUILD_DESKTOP=no BUILD_MINIMAL=yes
+    - env: RELEASE=bionic BUILD_DESKTOP=no BUILD_MINIMAL=yes
+    - env: RELEASE=buster BUILD_DESKTOP=no BUILD_MINIMAL=yes
+    # desktop build
+    - env: RELEASE=disco BUILD_DESKTOP=yes BUILD_MINIMAL=no
+    - env: RELEASE=bionic BUILD_DESKTOP=yes BUILD_MINIMAL=no
+    - env: RELEASE=buster BUILD_DESKTOP=yes BUILD_MINIMAL=no
 before_install:
   - sudo apt update
   - sudo apt install -y gnupg1 gpgv1 --no-install-recommends
@@ -55,11 +49,17 @@ before_script:
   - df -h
   - free -mh
   - sudo ccache -M 5.0G
+  - |
+    if [ -z "$TRAVIS_TAG" ] ; then
+      export KERNEL_ONLY="yes"
+    else
+      export KERNEL_ONLY="no"
+    fi
 script:
   - cd "$TRAVIS_BUILD_DIR" && touch .ignore_changes
   - |
     ./compile.sh BOARD=aml-g12 BRANCH=default RELEASE=$RELEASE BUILD_MINIMAL=$BUILD_MINIMAL BUILD_DESKTOP=$BUILD_DESKTOP \
-      KERNEL_ONLY=no KERNEL_CONFIGURE=no
+      KERNEL_ONLY=$KERNEL_ONLY KERNEL_CONFIGURE=no
 after_success:
   - df -h
   - free -mh