Use urllib.urlencode instead of dict_to_query_str

dict_to_query_str is only used to generate 'next' links
and this part of data is not used in a cinderclient now.
So it is safe to move forward and generate correct links right now.

Change-Id: I1d7a2e0bff3827011a787b70d7c54cd6a0b5de1f
Change CHAP secret default length

Some of the iSCSI initiators have a limit regarding the maximum
CHAP secret length. For example, the MS iSCSI Initiator
does not allow CHAP secrets longer than 16 characters, smaller
than the actual default 20 characters length.

This patch simply changes the default length to 16 characters,
value which is already used by default by some of the volume
drivers. In fact, the iSCSI specs state that: "Implementations
MUST support use of up to 128 bit random CHAP secrets".

Change-Id: I0295fabd0c0048c93e1f452077d0f5d19af9784d
Closes-Bug: #1392792
PureISCSIDriver needs to disconnect hosts before deleting volumes.

Some error conditions can cause a situation where the volume is
“connected” to a Purity host, but the volume failed to attach on the
initiator side. If we then try to delete this volume it will cause
errors and leave orphaned volumes behind on the Flash Array.

The solution is to check for any connections and then remove them prior
to making a call to delete the volume.

Closes-Bug: 1388260
Change-Id: I8f5b3b28900d79228fd91f2ad53535224f263657
Implementing the use of _L’x’/i18n markers

Placing the _Lx markers back into the code. No other cleaner solution has
has been implemented. Patches will be submitted in a series of sub
directories and in a fashion that is manageable.
This is the fourth commit of this kind

Change-Id: Ibbef7f06a391e9e6efca082d45caecdf60a9e811
Partial-Bug: #1384312
Fixup regressions in PureISCSIDriver log statements.

There were some conflicting patches that went in to fix i18n helpers,
and in the merge resolution we lost some changes that previously removed
all uses of .format() from the driver. This puts back in the updated
log statements originally added in 
https://review.openstack.org/#/c/135047/

Change-Id: I562a0dd950b88af2bdb67a135f6f6f0d258eed0e
Closes-Bug: 1395060
Merge "Change CHAP secret default length"
Merge "Implementing the use of _L’x’/i18n markers"
Merge "PureISCSIDriver needs to disconnect hosts before deleting volumes."
Merge "Fixup regressions in PureISCSIDriver log statements."
Merge "Use urllib.urlencode instead of dict_to_query_str"