Show scp output on error

communicator/ssh/communicator.go

@@ -693,6 +693,11 @@ func (c *comm) scpSession(scpCommand string, f func(io.Writer, *bufio.Reader) er
 			// Otherwise, we have an ExitErorr, meaning we can just read
 			// the exit status
 			log.Printf("non-zero exit status: %d", exitErr.ExitStatus())
+			stdoutB, err := ioutil.ReadAll(stdoutR)
+			if err != nil {
+				return err
+			}
+			log.Printf("scp output: %s", stdoutB)
 
 			// If we exited with status 127, it means SCP isn't available.
 			// Return a more descriptive error for that.