It must be an absolute path in gotools/Makefile

This fixes #FAB-2950

while doing "make gotools", I get an err which is that "cannot
install, GOBIN must be an absolute path." The path should be an
abspath path.

Change-Id: I86e42e3f6617d664ea4ba20601f5fb87553f027c
Signed-off-by: hanwei <499349274@qq.com>

gotools/Makefile

@@ -16,7 +16,7 @@ BINDIR ?= /usr/local/bin
 OBJDIR ?= build
 
 TMP_GOPATH=$(OBJDIR)/gopath
-GOBIN=$(TMP_GOPATH)/bin
+GOBIN=$(abspath $(TMP_GOPATH)/bin)
 
 GOTOOLS = golint govendor goimports protoc-gen-go ginkgo gocov gocov-xml
 GOTOOLS_BIN = $(patsubst %,$(GOBIN)/%, $(GOTOOLS))