title: Cant find package from $GOROOT and $GOPATH
body: <p>Small part of error I'm getting after trying to run go build command</p>
  
  <pre><code>go build ./...
  trillian.pb.go:7:8: cannot find package "github.com/golang/protobuf/proto" in any of:
      /usr/local/go/src/github.com/golang/protobuf/proto (from $GOROOT)
      /Projects/Proj1/trillian/src/github.com/golang/protobuf/proto (from $GOPATH)
  
  trillian.pb.go:11:8: cannot find package "github.com/golang/protobuf/ptypes/any" in any of:
      /usr/local/go/src/github.com/golang/protobuf/ptypes/any (from $GOROOT)
      /Projects/Proj1/trillian/src/github.com/golang/protobuf/ptypes/any (from $GOPATH)
  
  trillian_admin_api.pb.go:12:8: cannot find package "github.com/golang/protobuf/ptypes/empty" in any of:
      /usr/local/go/src/github.com/golang/protobuf/ptypes/empty (from $GOROOT)
      /Projects/Proj1/trillian/src/github.com/golang/protobuf/ptypes/empty (from $GOPATH)
  
  trillian.pb.go:10:8: cannot find package "github.com/google/trillian/crypto/sigpb" in any of:
      /usr/local/go/src/github.com/google/trillian/crypto/sigpb (from $GOROOT)
      /Projects/Proj1/trillian/src/github.com/google/trillian/crypto/sigpb (from $GOPATH)
  
  trillian_admin_api.pb.gw.go:17:2: cannot find package "github.com/grpc-ecosystem/grpc-gateway/runtime" in any of:
      /usr/local/go/src/github.com/grpc-ecosystem/grpc-gateway/runtime (from  $GOROOT)
      /Projects/Proj1/trillian/src/github.com/grpc-ecosystem/grpc-gateway/runtime (from $GOPATH)
  
  trillian_admin_api.pb.gw.go:18:2: cannot find package "github.com/grpc-ecosystem/grpc-gateway/utilities" in any of:
      /usr/local/go/src/github.com/grpc-ecosystem/grpc-gateway/utilities (from $GOROOT)
      /Projects/Proj1/trillian/src/github.com/grpc-ecosystem/grpc-gateway/utilities (from $GOPATH)
  
  trillian_admin_api.pb.go:15:2: cannot find package "golang.org/x/net/context" in any of:
      /usr/local/go/src/golang.org/x/net/context (from $GOROOT)
      /Projects/Proj1/trillian/src/golang.org/x/net/context (from $GOPATH)
  
  trillian_admin_api.pb.go:10:8: cannot find package "google.golang.org/genproto/googleapis/api/annotations" in any of:
      /usr/local/go/src/google.golang.org/genproto/googleapis/api/annotations (from $GOROOT)
      /Projects/Proj1/trillian/src/google.golang.org/genproto/googleapis/api/annotations (from $GOPATH)
  
  trillian_log_api.pb.go:65:8: cannot find package "google.golang.org/genproto/googleapis/rpc/status" in any of:
      /usr/local/go/src/google.golang.org/genproto/googleapis/rpc/status (from $GOROOT)
      /Projects/Proj1/trillian/src/google.golang.org/genproto/googleapis/rpc/status (from $GOPATH)
  
  trillian_admin_api.pb.go:11:8: cannot find package "google.golang.org/genproto/protobuf/field_mask" in any of:
      /usr/local/go/src/google.golang.org/genproto/protobuf/field_mask (from $GOROOT)
      /Projects/Proj1/trillian/src/google.golang.org/genproto/protobuf/field_mask (from $GOPATH)
  </code></pre>
  
  <p>Go env output</p>
  
  <pre><code>GOARCH="amd64"
  GOBIN=""
  GOEXE=""
  GOHOSTARCH="amd64"
  GOHOSTOS="linux"
  GOOS="linux"
  GOPATH="/Projects/Proj1/trillian"
  GORACE=""
  GOROOT="/usr/local/go"
  GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
  CC="gcc"
  GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build690359699=/tmp/go-build -gno-record-gcc-switches"
  CXX="g++"
  CGO_ENABLED="1"
  </code></pre>
  
  <p><code>GOPATH</code> and <code>GOROOT</code> are set but still can't run the command without errors. Tried installing to home and custom directories changing gopath and goroot regardless but still no luck. Any suggestions how to solve this?</p>