Files locked during installation [CR 465663]

On some UNIX systems (particularly AIX), files that the installer tries to update could be held in memory and locked. This problem usually resolves itself in subsequent runs of the installer. However, if the locks continue to be held, run sybinstall with the -unlock parameter added in 12.7 ESD #3. This parameter installs the files in a shadow directory, links to the correct location, then removes the shadow directory, thereby avoiding lock problems.