Merge pull request openshift#3165 from jim-minter/bz1373330

Document warnings returned by generic buildhook

Author: ahardin-rh

dev_guide/builds.adoc

@@ -1770,6 +1770,16 @@ and a payload. The `-H` argument sets the *Content-Type* header to
 The `--data-binary` argument is used to send a binary payload with newlines
 intact with the `*POST*` request.
 
+[NOTE]
+====
+{product-title} will permit builds to be triggered via the generic webhook even
+if an invalid request payload is presented (e.g. invalid content-type,
+unparseable or invalid content, etc.). This behaviour is maintained for
+backwards compatibility reasons. In the case that an invalid request payload is
+presented, {product-title} returns a warning in JSON format as part of its HTTP
+200 OK response.
+====
+
 [[describe-buildconfig]]
 
 *Displaying a BuildConfig's Webhook URLs*
@@ -2558,7 +2568,7 @@ The `*nodeSelector*` value can also be controlled by cluster-wide default and
 override values. Defaults will only be applied if the build configuration does
 not define any key/value pairs for the `*nodeSelector*` and also does not define
 an explicitly empty map value of "nodeSelector:{}". Override values will replace
-values in the build configuration on a key by key basis. 
+values in the build configuration on a key by key basis.
 
 ifdef::openshift-enterprise,openshift-origin[]
 See  xref:../install_config/build_defaults_overrides.adoc#overview[configuring