cli: Fix --boot smbios_mode=sysinfo (bz 1570549)

Not sure how this was expected to work, just make it do the simple
thing and set the value in the XML. Add a test case for it

tests/cli-test-xml/compare/virt-install-singleton-config-1.xml

@@ -18,6 +18,7 @@
     <type arch="x86_64">hvm</type>
     <loader readonly="yes" type="pflash">/usr/share/OVMF/OVMF_CODE.fd</loader>
     <boot dev="hd"/>
+    <smbios mode="emulate"/>
   </os>
   <features>
     <acpi/>

tests/clitest.py

@@ -386,7 +386,7 @@ c.add_compare(""" \
 --vcpus 4 --cpuset=1,3-5 \
 --cpu host \
 --description \"foobar & baz\" \
---boot uefi \
+--boot uefi,smbios_mode=emulate \
 --security type=dynamic \
 --security type=none,model=dac \
 --numatune 1,2,3,5-7,^6 \

virtinst/cli.py

@@ -1626,9 +1626,6 @@ class ParserBoot(VirtCLIParser):
         inst.set_initargs_string(val)
 
     def set_smbios_mode_cb(self, inst, val, virtarg):
-        if not val.startswith("emulate") and not val.startswith("host"):
-            inst.sysinfo.parse(val)
-            val = "sysinfo"
         inst.smbios_mode = val
         self.optdict["smbios_mode"] = val
 
@@ -1689,8 +1686,7 @@ ParserBoot.add_arg("kernel_args", "kernel_args",
 ParserBoot.add_arg("init", "init")
 ParserBoot.add_arg("machine", "machine")
 ParserBoot.add_arg("initargs", "initargs", cb=ParserBoot.set_initargs_cb)
-ParserBoot.add_arg("smbios_mode", "smbios_mode",
-                   can_comma=True, cb=ParserBoot.set_smbios_mode_cb)
+ParserBoot.add_arg("smbios_mode", "smbios_mode")
 
 # This is simply so the boot options are advertised with --boot help,
 # actual processing is handled by _parse