Update static/lib/js/ajax.js

Once hlfield is assigned the typeof hlfield check will never return true so the value never gets updated to a new one.

That means that the same message is repeated over and over once the first highlighted one has been found.

I'm no JavaScript expert (noob would be more like it) so there might be a more elegant fix for this.
Merge pull request #235 from lfrancke/patch-1

Fix highlighting problem
tweaking bug fix for #222 for multiple Smart_index_patterns
Merge pull request #237 from michaelgibson/kibana-ruby

tweaking bug fix for #222 for multiple Smart_index_patterns
fixed overlap of collapse button and column filter at lower resolutions
Cleanup ruby to 80 columns, fix for issue #230
Merge remote branch 'upstream/kibana-ruby' into kibana-ruby

Conflicts:
	static/lib/js/shared.js