Hide "-" in os without build.

pym/cl_fill_install.py

@@ -488,10 +488,12 @@ class fillVars(object, glob_attr):
     def get_os_disk_content(self):
         """Partition content"""
         return map(lambda x: x[1] if x[0] != '/' else
-                   "{short}-{march}-{build}".format(
+                   "{short}-{march}{build}".format(
                    short=self.Get('os_linux_shortname'),
                    march=self.Get('os_arch_machine'),
-                   build=self.Get('os_linux_build')),
+                   build="-%s"%(self.Get('os_linux_build') if
+                         self.Get('os_linux_build') else
+                         self.Get('os_linux_ver'))),
                zip(self.Get('os_disk_mount'),
                self.getAttributeFromHash('os_disk_hash','content')))