qvm-console-dispvm: drop wrong validation of trusted input

The previous code didn't allow "." in the VM name.  Input is trusted,
and besides invalid VM names will be rejected as nonexistent or
unstartable.

qvm-tools/qvm-console-dispvm

@@ -30,8 +30,6 @@ fi
 
 QREXEC_REQUESTED_TARGET="$1"
 
-[[ "$QREXEC_REQUESTED_TARGET" =~ ^[A-Za-z][A-Za-z0-9_-]*$ ]] || { printf 'Invalid qube name %q\n' "$QREXEC_REQUESTED_TARGET">&2; exit 1; }
-
 if "$do_start"; then
     msg='cannot be started'
     qvm-start --skip-if-running -- "$QREXEC_REQUESTED_TARGET"