CertUtils: export private key to pem format correctly

[yadvr]

This makes openssl rsa -in -check pass, due to "RSA" string the
validate of private key (pem file) by openssl fails. Also removes
a commented import.

Without this fix, in some systems the key/crt could not be reused. Following error was observed in openssl:
$ openssl rsa -in -check
RSA key ok
139832889164824:error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag:tasn_dec.c:1220:
139832889164824:error:0D06C03A:asn1 encoding routines:ASN1_D2I_EX_PRIMITIVE:nested asn1 error:tasn_dec.c:788:
139832889164824:error:0D08303A:asn1 encoding routines:ASN1_TEMPLATE_NOEXP_D2I:nested asn1 error:tasn_dec.c:720:Field=n, Type=RSA
139832889164824:error:04093004:rsa routines:OLD_RSA_PRIV_DECODE:RSA lib:rsa_ameth.c:121:

With this fix, the private key pem file will pass. Openssl output:
$ openssl rsa -in -check
RSA key ok
writing RSA key
-----BEGIN RSA PRIVATE KEY-----
...content of the file...

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)

How Has This Been Tested?

More Found this issue while refactoring/fixing CCS with ACS 4.11.1. With the fix, kubernetes api service could use CA framework issued certificates.

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
  Testing
• I have added tests to cover my changes.
• All relevant new and existing integration tests have passed.
• A full integration testsuite with all test that can run on my environment has passed.

[yadvr]

@blueorangutan package

[blueorangutan]

@rhtyd a Jenkins job has been kicked to build packages. I'll keep you posted as I make progress.

[blueorangutan]

Packaging result: ✔centos6 ✔centos7 ✔debian. JID-2329

[yadvr]

@blueorangutan test

[blueorangutan]

@rhtyd a Trillian-Jenkins test job (centos7 mgmt + kvm-centos7) has been kicked to run smoke tests

[GabrielBrascher]

Thanks for the fix @rhtyd!

[blueorangutan]

Trillian test result (tid-3056)
Environment: kvm-centos7 (x2), Advanced Networking with Mgmt server 7
Total time taken: 34842 seconds
Marvin logs: https://github.com/blueorangutan/acs-prs/releases/download/trillian/pr2875-t3056-kvm-centos7.zip
Intermittent failure detected: /marvin/tests/smoke/test_privategw_acl.py
Intermittent failure detected: /marvin/tests/smoke/test_public_ip_range.py
Intermittent failure detected: /marvin/tests/smoke/test_ssvm.py
Intermittent failure detected: /marvin/tests/smoke/test_templates.py
Intermittent failure detected: /marvin/tests/smoke/test_usage.py
Intermittent failure detected: /marvin/tests/smoke/test_vm_life_cycle.py
Intermittent failure detected: /marvin/tests/smoke/test_volumes.py
Intermittent failure detected: /marvin/tests/smoke/test_vpc_redundant.py
Intermittent failure detected: /marvin/tests/smoke/test_host_maintenance.py
Smoke tests completed. 63 look OK, 4 have error(s)
Only failed tests results shown below:

Test	Result	Time (s)	Test File
test_03_vpc_privategw_restart_vpc_cleanup	Failure	1100.24	test_privategw_acl.py
test_04_extract_template	Failure	128.32	test_templates.py
ContextSuite context=TestISOUsage>:setup	Error	0.00	test_usage.py
test_06_download_detached_volume	Failure	137.56	test_volumes.py