e2e tests: clean up antihelpful BeTrue()s

Many ginkgo tests have been written to use this evil form:

    GrepString("foo")
    Expect(that to BeTrue())

...which yields horrible useless messages on failure:

    false is not true

Identify those (automatically, via script) and convert to:

    Expect(output to ContainSubstring("foo"))

...which yields:

    "this output" does not contain substring "foo"

There are still many BeTrue()s left. This is just a start.

This is commit 1 of 2. It includes the script I used, and
all changes to *.go are those computed by the script.
Commit 2 will apply some manual fixes.

Signed-off-by: Ed Santiago <santiago@redhat.com>

test/e2e/import_test.go

@@ -87,7 +87,7 @@ var _ = Describe("Podman import", func() {
 		results := podmanTest.Podman([]string{"history", "imported-image", "--format", "{{.Comment}}"})
 		results.WaitWithDefaultTimeout()
 		Expect(results).Should(Exit(0))
-		Expect(results.LineInOutputStartsWith("importing container test message")).To(BeTrue())
+		Expect(results.OutputToStringArray()).To(ContainElement(HavePrefix("importing container test message")))
 	})
 
 	It("podman import with change flag CMD=<path>", func() {