MM-14574 Intercept log messages from local image proxy (#10668)

* MM-14574 Switch willnorris/imageproxy to fork

* MM-14574 Intercept log messages from local image proxy

* Revert "MM-14574 Switch willnorris/imageproxy to fork"

This reverts commit 046ab5c4216a5c6fee5bf8e2e0cceb1afffa6747.

* Update willnorris/imageproxy

vendor/modules.txt

@@ -359,6 +359,6 @@ gopkg.in/olivere/elastic.v5/uritemplates
 gopkg.in/yaml.v2
 # willnorris.com/go/gifresize v1.0.0
 willnorris.com/go/gifresize
-# willnorris.com/go/imageproxy v0.8.1-0.20190326225038-cf54b2cf2c9e
+# willnorris.com/go/imageproxy v0.8.1-0.20190326225038-d4246a08fdec
 willnorris.com/go/imageproxy
 willnorris.com/go/imageproxy/third_party/http