Fix mounts for directories with weird chars
Fixes:
`make -f docker.Makefile binary`
When directories have characters like `&&` they must be wrapped in
quotes or else the docker run command will fail.
DEV_DOCKER_IMAGE_NAME = docker-cli-dev
LINTER_IMAGE_NAME = docker-cli-lint
CROSS_IMAGE_NAME = docker-cli-cross
-MOUNTS = -v `pwd`:/go/src/github.com/docker/cli
+MOUNTS = -v "$(CURDIR)":/go/src/github.com/docker/cli
VERSION = $(shell cat VERSION)
ENVVARS = -e VERSION=$(VERSION) -e GITCOMMIT
