Make virCgroupIsValidMachine static

The virCgroupIsValidMachine does not need to be called from
outside the cgroups file now, so make it static.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/libvirt_private.syms

@@ -1186,7 +1186,6 @@ virCgroupGetMemSwapHardLimit;
 virCgroupGetMemSwapUsage;
 virCgroupHasController;
 virCgroupIsolateMount;
-virCgroupIsValidMachineGroup;
 virCgroupKill;
 virCgroupKillPainfully;
 virCgroupKillRecursive;

src/util/vircgroup.c

@@ -95,9 +95,10 @@ bool virCgroupAvailable(void)
     return ret;
 }
 
-bool virCgroupIsValidMachineGroup(virCgroupPtr group,
-                                  const char *name,
-                                  const char *drivername)
+static bool
+virCgroupIsValidMachineGroup(virCgroupPtr group,
+                             const char *name,
+                             const char *drivername)
 {
     size_t i;
     bool valid = false;

src/util/vircgroup.h

@@ -48,11 +48,6 @@ VIR_ENUM_DECL(virCgroupController);
 
 bool virCgroupAvailable(void);
 
-bool virCgroupIsValidMachineGroup(virCgroupPtr group,
-                                  const char *machinename,
-                                  const char *drivername);
-
-
 int virCgroupNewPartition(const char *path,
                           bool create,
                           int controllers,