[SPARK-4920][UI]:current spark version in UI is not striking.

[uncleGen]

It is not convenient to see the Spark version. We can keep the same style with Spark website.

[SparkQA]

Test build #24705 has started for PR 3763 at commit 0dcb9a9.

• This patch merges cleanly.

[SparkQA]

Test build #24705 has finished for PR 3763 at commit 0dcb9a9.

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

[AmplabJenkins]

Test PASSed.
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Test PASSed.

[andrewor14]

+1. I also thought the bottom greyed out text is too obscure. @JoshRosen any thoughts?

[JoshRosen]

@srowen commented on the JIRA:

I slight prefer the current UI, where the version is in the footer. Putting the version here pushes the tabs right significantly when the version is the long "1.3.0-SNAPSHOT". That said it is consistent with the web site. I imagine the necessary CSS is simple if they are both Bootstrap-based.

I prefer the CSS in this PR, but I also worry about long SNAPSHOT versions. That said, maybe it's not a huge deal on common screen resolutions.

[JoshRosen]

By the way, if we merge this it should also go into branch-1.1.

[srowen]

Meh, on looking at it again, I like the new version that's consistent with the website. It's only devs that will look at long SNAPSHOT names. It's a clean change too.

[andrewor14]

Alright, sounds good then I'm going to merge this into master 1.2 thanks guys.
For 1.1, it appears that there is a non-trivial merge conflict. @uncleGen would you mind opening a PR to back port this patch to branch 1.1? Thanks.

[ash211]

@andrewor14 would you mind merging this into branch-1.1 also? @JoshRosen pointed out it should go there too

[JoshRosen]

@ash211 I think that Andrew tried this, but there was a merge conflict:

For 1.1, it appears that there is a non-trivial merge conflict. @uncleGen would you mind opening a PR to back port this patch to branch 1.1? Thanks.

[ash211]

Oh whoops my apologies for the noise

[JoshRosen]

Branch-1.1 backport is here: #3768