Change default TurboOCI fstype to EROFS if images are supported

 - First, it has no impact if "ext4.fs.meta" exists only;
 - Second, it has no impact if the kernel doesn't support EROFS;
 - Third, only TurboOCI images built with "--fstype erofs" or
        where multiple fsmeta exists take effect;
 - Fourth, ".TurboOCI_ext4" is used for emergency fallback.

Signed-off-by: Gao Xiang <[email protected]>

Author: hsiangkao

pkg/snapshot/overlay.go

@@ -121,8 +121,8 @@ func DefaultBootConfig() *BootConfig {
 		RootfsQuota:       "",
 		Tenant:            -1,
 		TurboFsType: []string{
-			"ext4",
 			"erofs",
+			"ext4",
 		},
 	}
 }