CP-4946: PR-1634: Bulk import of FibreChannel LUNs in DR Wizard.

Added possibility to select/clear all rows on the Locate Mirrored SRs
page in the DR wizard.
CP-4946: PR-1634: Bulk import of FibreChannel LUNs in DR Wizard.

1. Resized columns on the LOcate Mirrored SRs page in the DR Wizard.
2. Changed wording of DR_WIZARD_STORAGEPAGE_DESCRIPTION_FAILBACK and
   DR_WIZARD_STORAGEPAGE_DESCRIPTION_FAILOVER messages.
CP-4946: PR-1634: Bulk import of FibreChannel LUNs in DR Wizard.

Fixed issue reported in review #1846.
Merge branch 'master' of git://hg.uk.xensource.com/carbon/trunk/xenadmin