clone depth of 1 and execute integration tests first

* specify git image

.drone.yml

 pipeline:
+  clone:
+    image: plugins/git
+    depth: 1
   jsunit:
     image: nextcloudci/jsunit:1.0.6
     commands:
@@ -9,7 +12,6 @@ pipeline:
   nodb-php5.6:
     image: nextcloudci/php5.6:php5.6-2
     commands:
-      - git submodule update --init
       - NOCOVERAGE=true TEST_SELECTION=NODB ./autotest.sh sqlite
     when:
       matrix:
@@ -18,7 +20,6 @@ pipeline:
   nodb-php7.0:
     image: nextcloudci/php7.0:php7.0-2
     commands:
-      - git submodule update --init
       - NOCOVERAGE=true TEST_SELECTION=NODB ./autotest.sh sqlite
     when:
       matrix:
@@ -27,7 +28,6 @@ pipeline:
   nodb-php7.1:
     image: nextcloudci/php7.1:php7.1-3
     commands:
-      - git submodule update --init
       - NOCOVERAGE=true TEST_SELECTION=NODB ./autotest.sh sqlite
     when:
       matrix:
@@ -36,7 +36,6 @@ pipeline:
   sqlite-php5.6:
     image: nextcloudci/php5.6:php5.6-2
     commands:
-      - git submodule update --init
       - NOCOVERAGE=true TEST_SELECTION=DB ./autotest.sh sqlite
     when:
       matrix:
@@ -45,7 +44,6 @@ pipeline:
   sqlite-php7.0:
     image: nextcloudci/php7.0:php7.0-2
     commands:
-      - git submodule update --init
       - NOCOVERAGE=true TEST_SELECTION=DB ./autotest.sh sqlite
     when:
       matrix:
@@ -54,7 +52,6 @@ pipeline:
   sqlite-php7.1:
     image: nextcloudci/php7.1:php7.1-3
     commands:
-      - git submodule update --init
       - NOCOVERAGE=true TEST_SELECTION=DB ./autotest.sh sqlite
     when:
       matrix:
@@ -64,7 +61,6 @@ pipeline:
     image: nextcloudci/php5.6:php5.6-2
     commands:
       - sleep 15 # gives the database enough time to initialize
-      - git submodule update --init
       - NOCOVERAGE=true TEST_SELECTION=DB ./autotest.sh mysql
     when:
       matrix:
@@ -74,7 +70,6 @@ pipeline:
     image: nextcloudci/php5.6:php5.6-2
     commands:
       - sleep 10 # gives the database enough time to initialize
-      - git submodule update --init
       - NOCOVERAGE=true TEST_SELECTION=DB ./autotest.sh pgsql
     when:
       matrix:
@@ -83,7 +78,6 @@ pipeline:
   integration:
     image: nextcloudci/php7.0:php7.0-2
     commands:
-      - git submodule update --init
       - ./occ maintenance:install --admin-pass=admin
       - cd build/integration
       - ./run.sh
@@ -93,6 +87,7 @@ pipeline:
 
 matrix:
   include:
+    - TESTS: integration
     - TESTS: jsunit
     - DB: NODB
       PHP: 5.6
@@ -110,7 +105,6 @@ matrix:
       PHP: 5.6
     - DB: postgres
       PHP: 5.6
-    - TESTS: integration
 
 services:
   cache: