storage: Fix broken storage_driver build
storage: Fix broken storage_driver build

Commit id '5d5c732d7' had an incorrect assignment and was found
by travis build:

storage/storage_driver.c:1668:14: error: equality comparison with extraneous
      parentheses [-Werror,-Wparentheses-equality]
    if ((obj == virStoragePoolObjListSearch(&driver->pools,

         ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

jardasgit/libvirt,andreabolognani/libvirt,jfehlig/libvirt,olafhering/libvirt,nertpinx/libvirt,eskultety/libvirt,andreabolognani/libvirt,libvirt/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,crobinso/libvirt,libvirt/libvirt,libvirt/libvirt,zippy2/libvirt,libvirt/libvirt,andreabolognani/libvirt,jardasgit/libvirt,nertpinx/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,eskultety/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,olafhering/libvirt,zippy2/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,eskultety/libvirt,crobinso/libvirt,andreabolognani/libvirt,eskultety/libvirt,jfehlig/libvirt,crobinso/libvirt,olafhering/libvirt,nertpinx/libvirt,jardasgit/libvirt,eskultety/libvirt,nertpinx/libvirt,zippy2/libvirt,crobinso/libvirt,zippy2/libvirt,jfehlig/libvirt,olafhering/libvirt,fabianfreyer/libvirt