Telegram parseMode option Markdown should be case-insensitive

[Appeltabak]

Kapacitor is unable to send alerts to Telegram when the option parseMode is set e.g. to markdown instead of Markdown:

[mbo_deadman:alert6] 2017/01/17 09:04:59 E! failed to send alert data to Telegram: parseMode markdown is not valid, please use 'Markdown' or 'HTML'

This occurred to me when using a template alert and template variables.

System info

Kapacitor 1.1.1 Official Docker image

[rossmcdonald]

Looking at the Telegram API reference here, it seems like Telegram expects the exact text Markdown or HTML (case-sensitive). If that's not the case, it should be a very quick fix to update the check to be case in-sensitive:

https://github.com/influxdata/kapacitor/blob/master/services/telegram/service.go#L146

We would accept a PR if someone wants to verify that the parse_mode text is not case-sensitive.

[Appeltabak]

I've tested this for both HTML and Markdown using random cased letters: the API is not case-sensitive:

[rossmcdonald]

@Appeltabak That's great. Would you like to submit a PR for that change? I can do it, if not.

[Appeltabak]

@rossmcdonald Yes, I'll try to submit one today

[dgellow]

I can see that The PR #1168 has been approved. Is there a reason it hasn't been merged?