Renaming a virtual machine through PowerCLI or any direct vCenter Server API script, and restarting the vCenter Server might revert the virtual machine name to its original value. The issue occurs as the VPX_ENTITY table is not updated, when you rename a virtual machine through PowerCLI.
This is fixed in vCenter Server 6.0 Update 2. If you see the issue even after upgrading to vCenter Server 6.0 Update 2, follow the steps mentioned in the below section.