capabilities: report full external snapshot support

Now that deleting and reverting external snapshots is implemented we can
report that in capabilities so management applications can use that
information and start using external snapshots.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>

tests/qemucaps2xmloutdata/caps.aarch64+hvf.xml

@@ -21,6 +21,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>
 

tests/qemucaps2xmloutdata/caps.aarch64.xml

@@ -21,6 +21,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>
 

tests/qemucaps2xmloutdata/caps.ppc.xml

@@ -19,6 +19,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>
 

tests/qemucaps2xmloutdata/caps.ppc64.xml

@@ -20,6 +20,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>
 

tests/qemucaps2xmloutdata/caps.riscv64.xml

@@ -19,6 +19,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>
 

tests/qemucaps2xmloutdata/caps.s390x.xml

@@ -20,6 +20,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>
 

tests/qemucaps2xmloutdata/caps.sparc.xml

@@ -19,6 +19,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>
 

tests/qemucaps2xmloutdata/caps.x86_64+hvf.xml

@@ -22,6 +22,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>
 

tests/qemucaps2xmloutdata/caps.x86_64.xml

@@ -22,6 +22,7 @@
       <cpuselection/>
       <deviceboot/>
       <disksnapshot default='on' toggle='no'/>
+      <externalSnapshot/>
     </features>
   </guest>