for #705; better error handling in loadOnly case - call obj.checkIntegrity()
for #705; better error handling in loadOnly case - call obj.checkIntegrity()

git-svn-id: 6d9763a5a770351123389058c013888add577529@13485 fe389314-cf27-0410-b35b-8c050e845b92

spacetelescope/stsci.tools