util: hook: use VIR_AUTOPTR for aggregate types

By making use of GNU C's cleanup attribute handled by the
VIR_AUTOPTR macro for declaring aggregate pointer variables,
majority of the calls to *Free functions can be dropped, which
in turn leads to getting rid of most of our cleanup sections.
Signed-off-by: NSukrit Bhatnagar <skrtbhtngr@gmail.com>
Reviewed-by: NErik Skultety <eskultet@redhat.com>

src/util/virhook.c

@@ -232,7 +232,7 @@ virHookCall(int driver,
 {
     int ret;
     VIR_AUTOFREE(char *) path = NULL;
-    virCommandPtr cmd;
+    VIR_AUTOPTR(virCommand) cmd = NULL;
     const char *drvstr;
     const char *opstr;
     const char *subopstr;
@@ -314,7 +314,5 @@ virHookCall(int driver,
                        virGetLastErrorMessage());
     }
 
-    virCommandFree(cmd);
-
     return ret;
 }