xm: fix description of xm vcpu-set command

Minor language correction in the description of the xm vcpu-set command.

Signed-off-by: Lalith Suresh <suresh.lalith@gmail.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/python/xen/xm/main.py

@@ -164,7 +164,7 @@ SUBCOMMAND_HELP = {
     'vcpu-pin'    : ('<Domain> <VCPU|all> <CPUs|all>',
                      'Set which CPUs a VCPU can use.'),
     'vcpu-set'    : ('<Domain> <vCPUs>',
-                     'Set the number of active VCPUs for allowed for the'
+                     'Set the number of active VCPUs allowed for the'
                      ' domain.'),
     #usb
     'usb-add'     : ('<domain> <[host:bus.addr] [host:vendor_id:product_id]>','Add the usb device to FV VM.'),