rust / build: make install should use explicit permissions when creating directories

Closes #10046
auto merge of #10048 : ibukanov/rust/mkdir-fix, r=brson

The patch replaces mkdir -p dir with (umask 022 && mkdir -p dir). Sadly mkdir -m 755 -p dir does not work if it creates parent directories as those parents will have umask permissions, not the one passed with -m option.   

Closes #10046