infra: fails build if checkstyle versions don't match with eclipse-cs

[rnveach]

After looking at #941 (comment) and options, we cannot combine POMs because eclipse-cs is not in maven, this is why we always have to install it before hand.

Instead, this change will manually verify checkstyle versions match up between different POMs. Fixed the first one where the main issue was identified.

This should fail without the referenced PR merged and should pass afterwards.

[rnveach]

https://app.travis-ci.com/github/sevntu-checkstyle/sevntu.checkstyle/jobs/589652909#L422
There is no message, but CI failed as expected where expected. Pushed an update to see if I can get the message to display.

CI should pass when #941 is merged

[rnveach]

Command is failing.

++ mvn -e -q -Dexec.executable=echo '-Dexec.args=${maven.sevntu.checkstyle.plugin.checkstyle.version}' --non-recursive org.codehaus.mojo:exec-maven-plugin:1.3.1:exec
+ ECLIPSE_CS_CS_VERSION='[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.3.1:exec (default-cli) on project net.sf.eclipsecs.parent: Command execution failed.: Process exited with an error: 1 (Exit value: 1) -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.3.1:exec (default-cli) on project net.sf.eclipsecs.parent: Command execution failed.

[rnveach]

POM variable is only available on 10.3.4 . We can't use this to test the current issue since the current issue is with 10.0.0 .

Travis was not showing the issue at all.

[rnveach]

Command fails with 10.4.0 as well. I am not sure why.

[coveralls]

Coverage remained the same at 98.798% when pulling 224647f on rnveach:eclipsecs_version_matcher into e0e2035 on sevntu-checkstyle:master.

[rnveach]

This won't work anyways. I am trying to pull in the verify time Checkstyle. They embed their JAR into the project, so I would need to verify a file name or something.