The plugin's dependency resolution seems to have problems with imported dependency management sections

I'm importing the dependency management of another pom that has managed versions for both spark and slf4j (1.7.12, a newer version than what spark requires), but the dependency version check fails:

```
[ERROR] Found a problem with the dependency org.slf4j:slf4j-api
  Resolved version is 1.7.10
  Version 1.7.12 was expected by artifacts: org.apache.spark:spark-core_2.10
```
