Support for cpu64-rhel* qemu cpu models

In qemu there are 2 cpu models (cpu64-rhel5 and cpu64-rhel6) not
supported by libvirt. This patch adds the support with the flags
specifications from /usr/share/qemu-kvm/cpu-model/cpu-x86_64.conf
The only difference is that AMD-specific features are removed so
the processor type is not vendor-specific. Those features are either
emulated or ignored by qemu if host CPU doesn't support them.

src/cpu/cpu_map.xml

@@ -303,6 +303,66 @@
       <feature name='pni'/>
     </model>
 
+    <model name='cpu64-rhel5'>
+      <feature name='apic'/>
+      <feature name='clflush'/>
+      <feature name='cmov'/>
+      <feature name='cx8'/>
+      <feature name='de'/>
+      <feature name='fpu'/>
+      <feature name='fxsr'/>
+      <feature name='lm'/>
+      <feature name='mca'/>
+      <feature name='mce'/>
+      <feature name='mmx'/>
+      <feature name='msr'/>
+      <feature name='mtrr'/>
+      <feature name='nx'/>
+      <feature name='pae'/>
+      <feature name='pat'/>
+      <feature name='pge'/>
+      <feature name='pse'/>
+      <feature name='pse36'/>
+      <feature name='sep'/>
+      <feature name='sse'/>
+      <feature name='sse2'/>
+      <feature name='pni'/>
+      <feature name='syscall'/>
+      <feature name='tsc'/>
+    </model>
+
+    <model name='cpu64-rhel6'>
+      <feature name='abm'/>
+      <feature name='apic'/>
+      <feature name='clflush'/>
+      <feature name='cmov'/>
+      <feature name='cx16'/>
+      <feature name='cx8'/>
+      <feature name='de'/>
+      <feature name='fpu'/>
+      <feature name='fxsr'/>
+      <feature name='lahf_lm'/>
+      <feature name='lm'/>
+      <feature name='mca'/>
+      <feature name='mce'/>
+      <feature name='mmx'/>
+      <feature name='msr'/>
+      <feature name='mtrr'/>
+      <feature name='nx'/>
+      <feature name='pae'/>
+      <feature name='pat'/>
+      <feature name='pge'/>
+      <feature name='pse'/>
+      <feature name='pse36'/>
+      <feature name='sep'/>
+      <feature name='sse'/>
+      <feature name='sse2'/>
+      <feature name='pni'/>
+      <feature name='sse4a'/>
+      <feature name='syscall'/>
+      <feature name='tsc'/>
+    </model>
+
     <model name='kvm32'>
       <model name='pentiumpro'/>
       <feature name='mtrr'/>