Build broken on master because of bundle actions command

[radu-matei]

#666 was merged earlier, but because the PR that removed the signing was merged before, this PR still referenced some methods that got changed, thus breaking the build:

$ make build
go build  -ldflags '-w -s -X github.com/deislabs/duffle/pkg/version.Version=0.1.0-ralpha.5+englishrose-44-gae6a7ca' -o /Users/radu/go/src/github.com/deislabs/duffle/bin/duffle github.com/deislabs/duffle/cmd/...
# github.com/deislabs/duffle/cmd/duffle
cmd/duffle/bundle_actions.go:45:42: too many arguments in call to resolveBundleFilePath
        have (string, string, bool, bool)
        want (string, string, bool)
cmd/duffle/bundle_actions.go:50:24: too many arguments in call to loadBundle
        have (string, bool)
        want (string)
make: *** [build] Error 2