Metrics with trailing slash are not handled properly

[danielnelson]

Bug report

Line protocol does not allow escaping of backslashes and as a result any measurement name, tag key, tag value, field key, field value that ends with a backslash is invalid.

In 1.3.3, items ending with a backslash may be parsed incorrectly potentially resulting in panic or malformed metrics.

influxdata/influxdb#5231

Relevant telegraf.conf:

System info:

[Include Telegraf version, operating system name, and other relevant details]

Steps to reproduce:

1. Create metrics with trailing slashes

Expected behavior:

Error? Removal of tailing slash?

Actual behavior:

Panic or malformed metric

Additional info:

[Include gist of relevant config, logs, etc.]

[danielnelson]

I am leaning towards automatic removal of trailing slash to avoid forcing all plugins to handle this.