makefile: simplify makefile version retrieval for compatibility (#842)

Makefile

@@ -57,18 +57,7 @@ endif
 
 RELEASE_VERSION =
 ifeq ($(RELEASE_VERSION),)
-	RELEASE_VERSION := v8.2.0-master
-	release_version_regex := ^v[0-9]\..*$$
-	release_branch_regex := "^release-[0-9]\.[0-9].*$$|^HEAD$$|^.*/*tags/v[0-9]\.[0-9]\..*$$"
-	ifneq ($(shell git rev-parse --abbrev-ref HEAD | grep -E $(release_branch_regex)),)
-		# If we are in release branch, try to use tag version.
-		ifneq ($(shell git describe --tags --dirty | grep -E $(release_version_regex)),)
-			RELEASE_VERSION := $(shell git describe --tags --dirty)
-		endif
-	else ifneq ($(shell git status --porcelain),)
-		# Add -dirty if the working tree is dirty for non release branch.
-		RELEASE_VERSION := $(RELEASE_VERSION)-dirty
-	endif
+	RELEASE_VERSION := $(shell git describe --tags --dirty)
 endif
 
 # Version LDFLAGS.