Fix build by dropping redefined typedefs

Commit 93e82727 introduced numatune_conf.h file that contains
typedefs already defined in domain_conf.h, such as:

 - virDomainNumatune
 - virDomainNumatunePtr
 - virDomainDef
 - virDomainDefPtr

As numatune_conf.h is included by domain_conf.h, clang
complains about redefinition of typedef and the build fails.

In order to fix it, drop typedefs already defined by numatume_conf.h
from domain_conf.h.

src/conf/domain_conf.h

@@ -67,9 +67,6 @@ typedef virDomainFSDef *virDomainFSDefPtr;
 typedef struct _virDomainNetDef virDomainNetDef;
 typedef virDomainNetDef *virDomainNetDefPtr;
 
-typedef struct _virDomainNumatune virDomainNumatune;
-typedef virDomainNumatune *virDomainNumatunePtr;
-
 typedef struct _virDomainInputDef virDomainInputDef;
 typedef virDomainInputDef *virDomainInputDefPtr;
 
@@ -1854,8 +1851,6 @@ struct _virDomainResourceDef {
  * NB: if adding to this struct, virDomainDefCheckABIStability
  * may well need an update
  */
-typedef struct _virDomainDef virDomainDef;
-typedef virDomainDef *virDomainDefPtr;
 struct _virDomainDef {
     int virtType;
     int id;