Fix the query to get all the AlarmStateHistory objects

It was using Alarm Definition Ids as Alarm Ids

Also, changed it to query Alarmed Metrics to match the given
dimensions instead of the Metric Definitions from the Alarm
Definition Expression. That allows you to get the alarms for a
specific host

Change-Id: I583b8ee017cad032a790de8861fffda07fdcc297
Fix alarm expression documentation

Change-Id: If3ed89b85651020afbaed47ea31d438bc53ed373
Fix alarm expression documentation

Change-Id: I0bbcac412ffcaab36bdab32fbb8474bc407811f6
Simplify list comprehension logic

Change-Id: I508172851f3baefe7464d6b4d10a1afeb4d84341
Merge "Simplify list comprehension logic"
Update alarm expression documentation

Change-Id: I9c41569e05ff7d1839af3c904d4e4ae78334ff6a
Merge "Update alarm expression documentation"
Update alarm expression BNF documentation

Change-Id: I78b2530a8aa9eec1a61ff08d8db2bb5dfc71ed8b
Merge "Update alarm expression BNF documentation"
Merge commit 'dbe8753d1a5878722bbb55cb28b5f226f095a20b'