qemu: Read back the profile name after creation of a TPM instance

qemu: Read back the profile name after creation of a TPM instance

Get the JSON profile that the swtpm instance was created with from the
output of 'swtpm socket --tpm2 --print-info 0x20 --tpmstate ...'. Get the
name of the profile from the JSON and set it in the current and persistent
emulator descriptions as 'name' attribute and have the persistent
description stored with this update. The user should avoid setting this
'name' attribute since it is meant to be read-only. The following is
an example of how the XML could look like:

  <profile source='local:restricted' name='custom:restricted'/>

If the user provided no profile node, and therefore swtpm_setup picked its
default profile, the XML may now shows the 'name' attribute with the name
of the profile. This makes the 'source' attribute now optional.

  <profile name='default-v1'/>

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>