Add ineffassign linter

Also enable GC in linting to reduce memory usage.

Signed-off-by: Daniel Nephin <dnephin@docker.com>
Upstream-commit: 09652bf8789142a5a5a1de2d41590300761b4954
Component: engine

components/engine/hack/dockerfile/binaries-commits

@@ -10,4 +10,4 @@ LIBNETWORK_COMMIT=7b2b1feb1de4817d522cc372af149ff48d25028e
 VNDR_COMMIT=9909bb2b8a0b7ea464527b376dc50389c90df587
 
 # Linting
-GOMETALINTER_COMMIT=f7b6e55301c9c67035003b7ba7f8a1cde532d338
+GOMETALINTER_COMMIT=5507b26af3204e949ffe50ec08ee73e5847938e1

components/engine/hack/validate/gometalinter.json

@@ -1,6 +1,7 @@
 {
   "Vendor": true,
   "Deadline": "2m",
+  "EnableGC": true,
   "Sort": ["linter", "severity", "path"],
   "Exclude": [
     ".*\\.pb\\.go",
@@ -17,6 +18,7 @@
     "gofmt",
     "goimports",
     "golint",
+    "ineffassign",
     "interfacer",
     "unconvert",
     "vet"