Fix/remove packr

[oleggator]

Docker image doesn't build.

Step 8/15 : RUN packr2 build -a -installsuffix cgo -tags=jsoniter -o geo-rest .
 ---> Running in dea6dee8c583
ERRO[2019-03-09T20:49:36Z] /go/src/golang.org/x/tools/go/loader/testdata/badpkgdecl.go: /go/src/golang.org/x/tools/go/loader/testdata/badpkgdecl.go:1:34: expected 'package', found 'EOF'
Error: /go/src/golang.org/x/tools/go/loader/testdata/badpkgdecl.go: /go/src/golang.org/x/tools/go/loader/testdata/badpkgdecl.go:1:34: expected 'package', found 'EOF'
Usage:
  packr2 build [flags]
Flags:
  -h, --help   help for build
Global Flags:
      --ignore-imports     when set to true packr won't resolve imports for boxes
      --legacy             uses the legacy resolution and packing system (assumes first arg || pwd for input path)
      --silent             silences all output
      --store-cmd string   sub command to use for packing
  -v, --verbose            enables verbose logging
The command '/bin/sh -c packr2 build -a -installsuffix cgo -tags=jsoniter -o geo-rest .' returned a non-zero code: 1
The command "docker build -t $DOCKERHUB_OWNER/geo-rest:$TRAVIS_COMMIT -f Dockerfile --cache-from teamd2018/geo-rest:latest ." exited with 1.