[Launch] Cannot launch debug first time just after adding launch.json

[adashen]

Steps:

1. Import a maven project
2. Add launch.json
3. F5 to debug
4. Fail to start
5. F5 again
6. Start debugging.

Expect:
should start after step 3.

[andxu]

log pops up: Cannot read property 'type' of undefined

[akaroml]

We need to fix this in 0.1.0. @andxu please take a look.

[andxu]

It is a vscode bug, cannot repro in insider version, I opened an issue in vscode side microsoft/vscode#34735

[andxu]

Verified at vscode 1.17, the bug is fiexed.