storage: improve the while loop virStorageBackendFileSystemIsMounted
storage: improve the while loop virStorageBackendFileSystemIsMounted

Move virStorageBackendFileSystemGetPoolSource outside of the while loop

Signed-off-by: Yi Li <55e7333d41158bbb5c693ad611d1d73461adffca@winhong.com>
Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

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