fix: Permission Denied on setns in 3.19- kernels

This commit fixes the issue where "setns" in older kernels will fail, as until 3.19 Linux used NSFS (Name Space File System) for namespaces (/proc/self/mnt/ns), which was not taken into consideration in ReZygisk SELinux rules.

module/src/sepolicy.rule

@@ -11,6 +11,7 @@ allow zygote su {lnk_file file} read
 allow zygote adb_data_file dir search
 allow zygote adb_data_file file *
 allow zygote proc file {read open}
+allow zygote nsfs file {read open}
 allow zygote zygote process execmem
 allow system_server system_server process execmem
 allow zygote tmpfs file *