Makefile: pick mockgen from env

        go install github.com/golang/mock/[email protected]
        export PATH=$PATH:$(go env GOPATH)/bin

Signed-off-by: Rohit Yadav <[email protected]>

Author: rohityadavcloud

Makefile

@@ -25,7 +25,7 @@ mocks:
 test:
 	go test -v github.com/apache/cloudstack-go/v2/test
 
-MOCKGEN ?= $(shell pwd)/bin/mockgen
+MOCKGEN := mockgen
 mockgen: ## Download conversion-gen locally if necessary.
 	$(call go-get-tool,$(MOCKGEN),github.com/golang/mock/mockgen)