e2e: accept context from Ginkgo

Every ginkgo callback should return immediately when a timeout occurs or the
test run manually gets aborted with CTRL-C. To do that, they must take a ctx
parameter and pass it through to all code which might block.

This is a first automated step towards that: the additional parameter got added
with

    sed -i 's/\(framework.ConformanceIt\|ginkgo.It\)\(.*\)func() {$/\1\2func(ctx context.Context) {/' \
        $(git grep -l -e framework.ConformanceIt -e ginkgo.It )
    $GOPATH/bin/goimports -w $(git status | grep modified: | sed -e 's/.* //')

log_test.go was left unchanged.

test/e2e/framework/internal/unittests/cleanup/cleanup_test.go

@@ -22,6 +22,7 @@ limitations under the License.
 package cleanup
 
 import (
+	"context"
 	"flag"
 	"regexp"
 	"testing"
@@ -77,7 +78,7 @@ var _ = ginkgo.Describe("e2e", func() {
 		framework.Logf("after #2")
 	})
 
-	ginkgo.It("works", func() {
+	ginkgo.It("works", func(ctx context.Context) {
 		// DeferCleanup invokes in first-in-last-out order
 		ginkgo.DeferCleanup(func() {
 			framework.Logf("cleanup last")