[HOTFIX] Rename the identifier of driver from <driver> to driver

[sarutak]

This change is related to #3812.

The identifier of driver is defined as <driver> but this identifier is used for metrics name and some metrics sinks cannot parse < and >.

[pwendell]

This could provide a usability regression for people since the name now appears differently in the UI. Is there any way we can intercept this somewhere downstream and not change it here?

[sarutak]

How about escaping specific characters like < or > in each sink instead of changing the identifier?

[sarutak]

I found this issue is resolved by updating com.codahale.metrics library from 3.0.0 to 3.1.0 and it's proposed in #4209. So I'll close this PR.

[SparkQA]

Test build #26221 has finished for PR 4245 at commit af59bf2.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[tsingfu]

@sarutak I found #4209 has not solved the problem invalid metric name with "" which introduced from #3812.
and I have a question: Is there difference between setting DRIVER_IDENTIFIER to "driver" and ""?