VMware:Unquote folder name for folder exists check

vCenter server escapes special characters in the folder name using URL
encoding and returns back the encoded string while querying. This causes
the check for folder existence to return false. Therefore, folder
creation is reattempted which eventually fails. This patch fixes the
problem by decoding the folder name returned by vCenter before
comparison.

Change-Id: I40aa6f42ea0d85fbfcb40970c55b20e13ea46522
Closes-Bug: #1356794