Ensure partition block size is not 0.

* I tried having this test in KDiskDeviceManager.cpp, but it
   failed booting in one case and did not solve the problem in another.
   I think this is because there is an Open() call here, and that rereads
   the blocksize.
 * Tested and it solved the problem for me.
 * Should fix #10717 and #9489 at least.

Signed-off-by: Jessica Hamilton <[email protected]>

src/system/kernel/disk_device_manager/KPartitioningSystem.cpp

@@ -69,6 +69,11 @@ KPartitioningSystem::Identify(KPartition *partition, void **cookie)
 	int fd = -1;
 	if (partition->Open(O_RDONLY, &fd) != B_OK)
 		return -1;
+
+	// if BlockSize is 0, identify_partition will cause a KDL
+	if (partition->BlockSize() == 0)
+		return -1;
+
 	float result = fModule->identify_partition(fd, partition->PartitionData(),
 		cookie);
 	close(fd);