issue#382 :Change false default value

Default value for pool and volume were passed when path parameter
is set. Fix this wrong behavior by delete the default values.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
issue#382: Validate form for adding guest cdrom

Add function for cdrom and disk form validation,
so that cdrom will not be created when no path given.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
Add mockmodel for vm disk attach

Add mockmodel for disk attach.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
Make sure path and volume will not be specified at same time

When adding vm storage, volume and path cannot be specified
at the same time. Fix it.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
Add testcase for vmstorages create

Add testcases to cover vmstorage create fails when
pool and path specified at the same time,
and vol not specified when pool is passed.

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>
Add translation for vm disk attach exceptions

Update pot and po for vm disk attach exceptions

Signed-off-by: Royce Lv <lvroyce@linux.vnet.ibm.com>