CP-2190 for PR-1221: performance alert for host memory use

Added perfmon defaults for "memory_total_kib" alert
(first part of CP-2190)

Signed-off-by: Thomas Sanders <thomas.sanders@citrix.com>
Slight correction and comment-update in perfmon

rrd_regex must match the whole data-source name, not just a substring

Signed-off-by: Thomas Sanders <thomas.sanders@citrix.com>
Changed dummy regex (in perfmon) to one that cannot match anything.

Signed-off-by: Thomas Sanders <thomas.sanders@citrix.com>
CP-2190 for PR-1221: performance alert for host sr throughput

Added perfmon defaults for "sr_io_throughput_total_xxxxxxxx" alert
for throughput on the SR whose uuid starts with xxxxxxxx.
(Second of two parts of CP-2190)

Signed-off-by: Thomas Sanders <thomas.sanders@citrix.com>
Fix a comment
In perfmon: add a workaround for CA-97947, and fix error-logging

In CA-97947 the xapi rpc call that creates the alert message has
become case-sensitive.
The workaround is to use the capitalisation it recognises.
Also the error-logging in perfmon could not handle Exceptions of
type XenAPI.Failure; now it can and is more robust.

Signed-off-by: Thomas Sanders <thomas.sanders@citrix.com>
Merge pull request #985 from thomassa/clearwater-pr1221

CP-2190 for PR-1221: host alerts for memory-use and sr-throughput