security/rhash: non-functional changes to prepare for update

• Chase HTTP/2 301 redirection in the WWW address
• Move USES et al. block above HAS_CONFIGURE where it should be normally found
• Reinstate MAKE_ARGS lost in r531582 (now commit 37cd5bfde4ba) and drop manual stripping in the `post-install' target
• Replace `do-test' target with equivalent TEST_TARGET knob

PR: 283630, 290603