build: avoid uninitialized use warning
build: avoid uninitialized use warning

Otherwise, with new enough gcc compiling at -O2, the build fails with:
../../src/conf/domain_conf.c: In function ‘virDomainDeviceDefPostParse’:
../../src/conf/domain_conf.c:2821:29: error: ‘cnt’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
             for (i = 0; i < *cnt; i++) {
                             ^
../../src/conf/domain_conf.c:2795:20: note: ‘cnt’ was declared here
         size_t i, *cnt;
                    ^
../../src/conf/domain_conf.c:2794:30: error: ‘arrPtr’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
         virDomainChrDefPtr **arrPtr;
                              ^

* src/conf/domain_conf.c (virDomainChrGetDomainPtrs): Always
assign into output parameters.

Signed-off-by: Eric Blake <a9da18479c871fe903d9590822cfe2629c6a4d11@redhat.com>

zippy2/libvirt,fabianfreyer/libvirt,elmarco/libvirt,rlaager/libvirt,shugaoye/libvirt,eskultety/libvirt,jfehlig/libvirt,rlaager/libvirt,VenkatDatta/libvirt,datto/libvirt,nertpinx/libvirt,crobinso/libvirt,zippy2/libvirt,jfehlig/libvirt,jfehlig/libvirt,olafhering/libvirt,taget/libvirt,agx/libvirt,zhlcindy/libvirt-1.1.4-maintain,cbosdo/libvirt,andreabolognani/libvirt,taget/libvirt,zippy2/libvirt,taget/libvirt,andreabolognani/libvirt,libvirt/libvirt,zhlcindy/libvirt-1.1.4-maintain,shugaoye/libvirt,agx/libvirt,andreabolognani/libvirt,datto/libvirt,libvirt/libvirt,jardasgit/libvirt,datto/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,cbosdo/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,shugaoye/libvirt,rlaager/libvirt,eskultety/libvirt,libvirt/libvirt,fabianfreyer/libvirt,elmarco/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,taget/libvirt,jardasgit/libvirt,shugaoye/libvirt,olafhering/libvirt,nertpinx/libvirt,taget/libvirt,libvirt/libvirt,jardasgit/libvirt,datto/libvirt,rlaager/libvirt,rlaager/libvirt,andreabolognani/libvirt,eskultety/libvirt,zhlcindy/libvirt-1.1.4-maintain,VenkatDatta/libvirt,VenkatDatta/libvirt,datto/libvirt,cbosdo/libvirt,elmarco/libvirt,zhlcindy/libvirt-1.1.4-maintain,elmarco/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,agx/libvirt,cbosdo/libvirt,zhlcindy/libvirt-1.1.4-maintain,agx/libvirt,crobinso/libvirt,zippy2/libvirt,crobinso/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,olafhering/libvirt,nertpinx/libvirt,cbosdo/libvirt,olafhering/libvirt,nertpinx/libvirt,shugaoye/libvirt,eskultety/libvirt,eskultety/libvirt,elmarco/libvirt,agx/libvirt,crobinso/libvirt