add is_repo_sync support

config.txt

@@ -1,8 +1,9 @@
 user_password=default
 working_dir=default
 repo_branch=default
-build_packages=true
-build_firmware=true
-build_image=true
-install_image=true
+is_repo_sync=true
+is_build_packages=true
+is_build_firmware=true
+is_build_image=true
+is_install_image=true
 dut_ip_addr=192.168.1.2