Merge PR #3441: Small fixes for Makefile

- Remove --long from git describe. Appending commit info on tagged
  revisions is redundant.
- $(subst v,,$(shell git describe --tags --long)) was removing any
  occurrence of 'v'. Rather we want to remove only the 'v' prefix
  from tags.

Makefile

@@ -1,6 +1,6 @@
 PACKAGES_NOSIMULATION=$(shell go list ./... | grep -v '/simulation')
 PACKAGES_SIMTEST=$(shell go list ./... | grep '/simulation')
-VERSION := $(subst v,,$(shell git describe --tags --long))
+VERSION := $(shell echo $(shell git describe --tags) | sed 's/^v//')
 COMMIT := $(shell git log -1 --format='%H')
 BUILD_TAGS = netgo
 CAT := $(if $(filter $(OS),Windows_NT),type,cat)