Use external pre-baked docker image for fedora tests to speed them up

.travis.yml

@@ -5,7 +5,7 @@ script:
     - ./test 
 
 env:
-    - DETECTED_OS=fedora:24
+    - DETECTED_OS=fedora:24 DOCKER_IMAGE=cyplo/fedora24_base NO_COMPILE_VIM=true
     - DETECTED_OS=debian:jessie NOUPGRADE=true
     - DETECTED_OS=ubuntu:trusty
     - DETECTED_OS=ubuntu:xenial

fedora/configure_fresh_system

@@ -25,6 +25,7 @@ if [[ -z $NO_SYSTEMCTL ]]; then
     sudo systemctl list-timers "*dnf-*"
 fi
 
+if [[ -z $NO_COMPILE_VIM ]]; then
     VIM_BUILD_DIR=/tmp
     cd "$VIM_BUILD_DIR"
     git clone https://github.com/vim/vim.git
@@ -40,6 +41,7 @@ make -j2
     sudo make install
     cd
     rm -fvr "$VIM_BUILD_DIR/vim"
+fi
 
 DIR="$DIR/../"
 DIR="$DIR" $DIR/common/configure_fresh_system

test

@@ -25,5 +25,9 @@ else
     DIR=$SYSTEM_DIR
 fi
 
-docker run -v $CURRENT_DIR:$INSIDER_ROOT_DIR $DETECTED_OS $INSIDER_ROOT_DIR/$DIR/test_insider
+if [[ -z $DOCKER_IMAGE ]]; then
+    DOCKER_IMAGE="$DETECTED_OS"
+fi
+
+docker run -v $CURRENT_DIR:$INSIDER_ROOT_DIR $DOCKER_IMAGE $INSIDER_ROOT_DIR/$DIR/test_insider