Allow additional arguments to be passed into hooks

If a packager wants to be able to support addititional arguments on his
hook this will allow them to setup the configuration with these arguments.

For example this would allow a hook developer to add support for a --debug
flag to change the level of debugging in his hook.

In order to complete this task, I had to vendor in the latest
github.com://opencontainers/runtime-tools, which caused me to have to fix a
Mount and Capability interface calls

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

lib/hooks.go

@@ -27,6 +27,7 @@ type HookParams struct {
 	Cmds          []string `json:"cmd"`
 	Annotations   []string `json:"annotation"`
 	HasBindMounts bool     `json:"hasbindmounts"`
+	Arguments     []string `json:"arguments"`
 }
 
 // readHook reads hooks json files, verifies it and returns the json config