fixes for tests

*   Remove google chart url test, as this chart no longer exists
*   make tests use `-cpu=4` to avoid flakey httpbin, as httpbin itself
    starts to 50x if called with _too much_ concurrency.

Makefile

@@ -82,7 +82,7 @@ build: setup
 
 test: setup
 	@echo "Running tests..."
-	@go test -count=1 -vet=off ${GOTEST_FLAGS} ./...
+	@go test -count=1 -cpu=4 -vet=off ${GOTEST_FLAGS} ./...
 
 bench: setup
 	@echo "Running benchmarks..."

pkg/camo/proxy_test.go

@@ -58,13 +58,6 @@ func TestSimpleValidImageURL(t *testing.T) {
 	}
 }
 
-func TestGoogleChartURL(t *testing.T) {
-	t.Parallel()
-	testURL := "http://chart.apis.google.com/chart?chs=920x200&chxl=0:%7C2010-08-13%7C2010-09-12%7C2010-10-12%7C2010-11-11%7C1:%7C0%7C0%7C0%7C0%7C0%7C0&chm=B,EBF5FB,0,0,0&chco=008Cd6&chls=3,1,0&chg=8.3,20,1,4&chd=s:AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA&chxt=x,y&cht=lc"
-	_, err := makeTestReq(testURL, 200, camoConfig)
-	assert.Check(t, err)
-}
-
 func TestChunkedImageFile(t *testing.T) {
 	t.Parallel()
 	testURL := "https://www.igvita.com/posts/12/spdyproxy-diagram.png"