Fix panic caused by invalid ip range

[xiangpengzhao]

If an invalid ip range such as 1.2.3-4 is passed to ipfailover, it will lead to a panic. I produce the panic in unit test by adding an invalid ip range in test cases. I haven't produced it on real env yet, but I think it will have the same behavior.

--- FAIL: TestValidateIPAddressRange (0.00s)
panic: runtime error: index out of range [recovered]
    panic: runtime error: index out of range

goroutine 15 [running]:
panic(0x1740000, 0xc82000e070)
    /usr/local/go/src/runtime/panic.go:464 +0x3ff
testing.tRunner.func1(0xc8203d61b0)
    /usr/local/go/src/testing/testing.go:467 +0x22a
panic(0x1740000, 0xc82000e070)
    /usr/local/go/src/runtime/panic.go:426 +0x521
github.com/openshift/origin/pkg/ipfailover.ValidateIPAddressRange(0x1934438, 0x7, 0x0, 0x0)
    github.com/openshift/origin/pkg/ipfailover/_test/_obj_test/validator.go:38 +0x1064
github.com/openshift/origin/pkg/ipfailover.TestValidateIPAddressRange(0xc8203d61b0)
    /root/go/src/github.com/openshift/origin/_output/local/go/src/github.com/openshift/origin/pkg/ipfailover/validator_test.go:49 +0x426
testing.tRunner(0xc8203d61b0, 0x24970d8)
    /usr/local/go/src/testing/testing.go:473 +0xdd
created by testing.RunTests
    /usr/local/go/src/testing/testing.go:582 +0xae3
FAIL    github.com/openshift/origin/pkg/ipfailover  0.079s
[ERROR] PID 26569: hack/test-go.sh:299: `go test ${gotest_flags} ${test_packages}` exited with status 1.
[INFO]      Stack Trace: 
[INFO]        1: hack/test-go.sh:299: `go test ${gotest_flags} ${test_packages}`
[INFO]   Exiting with code 1.
hack/test-go.sh failed after 56 seconds

Also add a validation for invalid format of ip range such as 1.2.3.4-5-6.

Maybe we can make more cleanup for func ValidateIPAddressRange

[mfojtik]

LGTM [merge]

[xiangpengzhao]

Test failed due to #9195 . @mfojtik Please help to request a re-test, thanks!

[stevekuznetsov]

@openshift-bot, the last build failed from the following flakes:

• conformance failed on: devmapper driver flake #9548 [builds][Conformance] build without output image #9490

re[merge]

[openshift-bot]

Evaluated for origin merge up to 88ee27c

[openshift-bot]

continuous-integration/openshift-jenkins/merge SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pr_origin/7546/) (Image: devenv-rhel7_4764)