Better error handling in MethodOverride

[troelskn]

This commit: 9a4140a made a change to suppress parse errors in the MethodOverride middleware. I suppose this is fine in production, but I just spent half a day tracking down why my rails app was ignoring _method and treating tunnelled PATCH requests as POST. In order to save some other poor soul from the same ill fate, I would suggest to log a warning of some kind when this happens - or perhaps fall back on a less strict parser (not sure how good an idea that is though).

[jeremyevans]

This seems like a useful feature. Let's continue the conversation in #1019.

[ioquatix]

@jeremyevans I love your optimism "Let's continue the conversation" on a 4 year old issue. Thank you for being so gracious :)