Fixup: Handle cpu util failures on non implemented arch

Some of the cpu utils are not implemented yet for certain cpu
arch yet due to which we would encounter below error,
during the vt-bootstrap

    create_host_os_cfg(options)
  File ".../virttest/bootstrap.py", line 355, in create_host_os_cfg
    family = cpu.get_family() if hasattr(cpu, 'get_family') else None
  File ".../avocado/avocado/utils/cpu.py", line 188, in get_family
    raise NotImplementedError
NotImplementedError

Let's handle the same, additionaly populate the vendor
information in the config only if available.
Reported-by: NYanan Fu <yfu@redhat.com>
Signed-off-by: NSatheesh Rajendran <sathnaga@linux.vnet.ibm.com>

virttest/bootstrap.py

@@ -352,7 +352,12 @@ def create_host_os_cfg(options):
         arch = _forced_or_detected(get_opt(options, 'vt_host_distro_arch'),
                                    "Host_arch_%s" % detected.arch)
         vendor = cpu.get_vendor() if hasattr(cpu, 'get_vendor') else cpu.get_cpu_vendor_name()
-        family = cpu.get_family() if hasattr(cpu, 'get_family') else None
+        family = None
+        if hasattr(cpu, 'get_family'):
+            try:
+                family = cpu.get_family()
+            except NotImplementedError:
+                pass
         cpu_version = cpu.get_version() if hasattr(cpu, 'get_version') else None
 
         cfg.write("variants:\n")
@@ -365,10 +370,11 @@ def create_host_os_cfg(options):
         cfg.write("                            - @%s:\n" % release)
         cfg.write("                                variants:\n")
         cfg.write("                                    - @%s:\n" % arch)
-        cfg.write("variants:\n")
-        cfg.write("    - @HostCpuVendor:\n")
-        cfg.write("        variants:\n")
-        cfg.write("            - @%s:\n" % vendor)
+        if vendor:
+            cfg.write("variants:\n")
+            cfg.write("    - @HostCpuVendor:\n")
+            cfg.write("        variants:\n")
+            cfg.write("            - @%s:\n" % vendor)
         if family:
             cfg.write("variants:\n")
             cfg.write("    - @HostCpuFamily:\n")