Fixed: Failing file copy when running in docker on synology with btrfs

Co-Authored-By: Taloth <Taloth@users.noreply.github.com>
Signed-off-by: Robin Dadswell <robin@dadswell.email>

src/NzbDrone.Mono/Interop/NativeMethods.cs

@@ -17,7 +17,7 @@ internal static class NativeMethods
 
         public static SafeUnixHandle open(string pathname, OpenFlags flags)
         {
-            return new SafeUnixHandle(Syscall.open(pathname, flags));
+            return new SafeUnixHandle(Syscall.open(pathname, flags, FilePermissions.DEFFILEMODE));
         }
 
         internal static int clone_file(SafeUnixHandle link_fd, SafeUnixHandle src_fd)