When BE sets `ignore_broken_disk` to true, it's expected that non-exist path in storage_root_path won't prevent BE from launching, but in 0.12 BE fails to launch in such scenario.
```
W0506 14:46:11.039953 17040 options.cpp:64] path can not be canonicalized. may be not exist. path=/data11/olap
W0506 14:46:11.040014 17040 options.cpp:141] failed to parse store path /data11/olap, res=-203
```
The reason is that #2861 adds a path existence check in `parse_root_path` which precedes the usage of `ignore_broken_disk` in the main method.
2f7d2c7e1a