Modifiers are not honored in `patterns` config option

[nathanielc]

I expected the following logparser config to create a port tag and packets, bytes as integer fields. But instead I got three string fields and no tags:

[[inputs.logparser]]
   files = ["/var/lib/pmacct/in_port.txt"]
   from_beginning = true
   [inputs.logparser.grok]
     patterns = ["%{NONNEGINT:port:tag},%{NONNEGINT:packets:int},%{NONNEGINT:bytes:int}"]

This config on the other hand worked, which uses the custom_patterns config option.

[[inputs.logparser]]
   files = ["/var/lib/pmacct/in_port.txt"]
   from_beginning = true
   [inputs.logparser.grok]
     measurement = "net_in_port"
     patterns = ["%{CSV_PORT}"]
     custom_patterns = '''
CSV_PORT %{NONNEGINT:port:tag},%{NONNEGINT:packets:int},%{NONNEGINT:bytes:int}
'''

Either the patterns config needs to error if the patterns contain modifiers or they need to work.

Version: 1.0.0-beta2