Single quote iniset argument in merge_config_file

If we don't single quote the extracted argument to iniset we drop any
quotes from the source.  Add a simple test-case for this.

Partial-bug: #1374118

Change-Id: If2f47b64b11015e727a011c7e5f6e8ad378b90eb
Enable DIB service to build with minimal net access

Adds two new options to lib/dib that will help devstack slaves
use cached content and content local to cloud provides:

 * DIB_BUILD_OFFLINE: This will enable DIB to rely entirely on
   cached images without making any additional calls to cloud-images.ubuntu.com
   to validate hashes/freshness.

 * DIB_APT_SOURCES: Used to specify alternatve sources.list for image builds.
   Setting this enables the addition of the apt-sources element during image
   builds and is only supported for ubuntu/debian builds.

Change-Id: I9b9ca72ec551565d454610aacb86c585f0384f13
Partial-bug: #1375488
Fix account rc files creation for Swift users

Id02ebdfa5cb3f6c763293876c6bb031184ebd663 introduced a small
regression which makes the command x509-create-cert fail with
'ERROR (CommandError): Invalid OpenStack Nova credentials.' for
Swift users.

The handling of specific password for Swift users was introduced
in Ifb57a43aad439ffe041e98465719a8a8eceae544

Change-Id: I3f328b1358bad0bdf7056796eabfe846dd5bae3a
Replace deprecated conf option for heat

Change-Id: I0419b188ecc2bd946c1c1f565875c6a04f4afd9b
Closes-Bug: #1379234
Merge "Single quote iniset argument in merge_config_file"
Merge "Replace deprecated conf option for heat"
Merge "Enable DIB service to build with minimal net access"
Merge "Fix account rc files creation for Swift users"