Ignore If-Modified-Since when If-None-Match is set

[slozier]

From RFC 7232:

A recipient MUST ignore If-Modified-Since if the request contains an
If-None-Match header field; the condition in If-None-Match is
considered to be a more accurate replacement for the condition in
If-Modified-Since, and the two are only combined for the sake of
interoperating with older intermediaries that might not implement
If-None-Match.

[thecodejunkie]

Thanks!