Fix commit count in travis' build

.travis.yml

@@ -1,6 +1,9 @@
 language: android
 android:
   components:
+  - tools
+  - platform-tools
+  - tools
   - build-tools-26.0.1
   - android-26
   - extra-android-m2repository

.travis/build.sh

@@ -1,9 +1,10 @@
 #!/bin/bash
 
+git fetch --unshallow #required for commit count
+
 if [ -z "$TRAVIS_TAG" ]; then
     ./gradlew clean buildStandardDebug
 
-    git fetch --unshallow #required for commit count
     COMMIT_COUNT=$(git rev-list --count HEAD)
     export ARTIFACT="tachiyomi-r${COMMIT_COUNT}.apk"