Log provider assumptions

[rmc3]

Added info logging of provider assumptions when checking if a Dockerfile exists in workflows/service_common.go

fixes #304

[rmc3]

Uncertain why the tests failed, I didn't expect this commit to make changes that would affect CFN template rendering at all, much less in a fashion that'd set off cfn_nag.

[rmc3]

tests currently pass for me locally

Richs-MacBook-Pro:mu rmc3$ git log | head -n 12
commit e34fcab1faecced2bf96f968a02a20e9a8ab69b6
Author: Rich Chatterton <rich.m.chatterton@gmail.com>
Date:   Tue Apr 10 18:19:58 2018 -0500

    Added info logging of provider assumptions when checking if a Dockerfile exists in service_common.go

commit b294e885891cab33019a3ddf0ae0c3196dce751d
Author: Casey Lee <casey.lee@stelligent.com>
Date:   Tue Apr 10 16:35:02 2018 -0700

    Fix #306 by

Richs-MacBook-Pro:mu rmc3$ make test
=== formatting ===
go fmt  ./provider/...  ./workflows/...  ./cli/...  ./common/...  ./templates/...  ./e2e/... .
templates/assets.go
=== linting ===
go vet  ./provider/...  ./workflows/...  ./cli/...  ./common/...  ./templates/...  ./e2e/... .
echo  ./provider/...  ./workflows/...  ./cli/...  ./common/...  ./templates/...  ./e2e/... . | xargs -n1 golint -set_exit_status
go generate  ./provider/...  ./workflows/...  ./cli/...  ./common/...  ./templates/...  ./e2e/... .
=== cfn_nag ===
=== cyclomatic complexity ===
30 aws (*cloudformationStackManager).UpsertStack provider/aws/cloudformation.go:100:1
21 workflows (*environmentWorkflow).environmentUpserter workflows/environment_upsert.go:281:1
20 workflows (*pipelineWorkflow).pipelineUpserter workflows/pipeline_upsert.go:197:1
20 aws InitializeContext provider/aws/init.go:15:1
19 aws (*cloudformationStackManager).AwaitFinalStatus provider/aws/cloudformation.go:274:1
18 workflows (*serviceWorkflow).serviceApplyCommonParams workflows/service_deploy.go:213:1
18 common newTemplateArchiveExtension common/extension.go:221:1
16 aws (*s3ArtifactManager).GetArtifact provider/aws/s3.go:66:1
WARNING: cyclomatic complexity is high
=== testing ===
go test -cover ./provider/... ./workflows/... ./cli/... ./common/... ./templates/... . -short
ok  	github.com/stelligent/mu/provider/aws	(cached)	coverage: 57.5% of statements
ok  	github.com/stelligent/mu/workflows	(cached)	coverage: 46.7% of statements
ok  	github.com/stelligent/mu/cli	(cached)	coverage: 33.1% of statements
ok  	github.com/stelligent/mu/common	(cached)	coverage: 25.0% of statements
ok  	github.com/stelligent/mu/templates	(cached)	coverage: 64.4% of statements
ok  	github.com/stelligent/mu	(cached)	coverage: 100.0% of statements
Richs-MacBook-Pro:mu rmc3$ echo $?
0