tizenrt: build: Update TizenRT to 2.0_Public_M2

Because current version of TizenRT in IoT.js docker image is outdated,
let's fetch tag from upstream at build time,
to speed up build time, this part can be eventually removed
if image is updated with latest TizenRT's sources.

Bug: jerryscript-project#1777
Forwarded: jerryscript-project#1780
IoT.js-DCO-1.0-Signed-off-by: Philippe Coval p.coval@samsung.com

tools/travis_script.py

@@ -44,7 +44,7 @@
 
 DOCKER_NAME = 'iotjs_docker'
 BUILDTYPES = ['debug', 'release']
-TIZENRT_TAG = '1.1_Public_Release'
+TIZENRT_TAG = '2.0_Public_M2'
 
 # Common buildoptions for sanitizer jobs.
 BUILDOPTIONS_SANITIZER = [
@@ -137,6 +137,7 @@ def build_iotjs(buildtype, args=[], env=[]):
                         '--profile=test/profiles/rpi2-linux.profile'])
 
     elif test == 'artik053':
+        exec_docker(DOCKER_TIZENRT_PATH, ['git', 'fetch', '--tags'])
         # Checkout specified tag
         exec_docker(DOCKER_TIZENRT_PATH, ['git', 'checkout', TIZENRT_TAG])
         # Set configure