Fixes raw templates not downloading

[Spaceman1984]

Description

This PR fixes an error where raw template files are not being downloaded

Fixes: #2820

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)

Screenshots (if appropriate):

How Has This Been Tested?

This was tested by adding a raw template to be downloaded from the UI

[Spaceman1984]

@blueorangutan package

[blueorangutan]

@Spaceman1984 a Jenkins job has been kicked to build packages. I'll keep you posted as I make progress.

[blueorangutan]

Packaging result: ✔centos7 ✔debian. JID-1096

[DaanHoogland]

testing, very risk poor change (downloading/image store only.

[blueorangutan]

Trillian test result (tid-1326)
Environment: kvm-centos7 (x2), Advanced Networking with Mgmt server 7
Total time taken: 26195 seconds
Marvin logs: https://github.com/blueorangutan/acs-prs/releases/download/trillian/pr3993-t1326-kvm-centos7.zip
Intermittent failure detected: /marvin/tests/smoke/test_privategw_acl.py
Smoke tests completed. 76 look OK, 1 have error(s)
Only failed tests results shown below:

Test	Result	Time (s)	Test File
test_02_vpc_privategw_static_routes	Failure	167.82	test_privategw_acl.py
test_03_vpc_privategw_restart_vpc_cleanup	Failure	167.85	test_privategw_acl.py
test_04_rvpc_privategw_static_routes	Failure	224.70	test_privategw_acl.py

[andrijapanicsb]

LGTM

Tested with http://download.cloudstack.org/testing/CentOS-7-x86_64-GenericCloud-1511.raw.bz2 (temp abuse of the hosting, due to lack of availability of raw.bz2 images online on plain HTTP)

Works fine, downloaded, unpacked, and eventually Ready.

[DaanHoogland]

tested and code lgtm

[andrijapanicsb]

2 x approvals, automated regression tests fine, manual (fix) tests fine.

Merging based on ^^^