This commit is to enhance the 'software upload-dir' to handle when
the given parameter is invalid, and to improve the error messages to
indicate the error that occurred.
[sysadmin@controller-0 ~(keystone_admin)]$ software upload-dir abc
Invalid release directory: abc
No files to upload
[sysadmin@controller-0 ~(keystone_admin)]$
Test Plan:
PASS: run 'software upload-dir' with invalid directory
PASS: run 'software upload-dir' with valid directory
Task: 49527
Story: 2010676
Change-Id: I73a82eac713ec90e3df1ea70b033c3ddf1368910