fix(dist/arm): don't assume armv7 if /proc/cpuinfo is unavailable

Author: rami3l

rustup-init.sh

@@ -540,7 +540,7 @@ get_architecture() {
     # and fall back to arm.
     # See https://github.com/rust-lang/rustup.rs/issues/587.
     if [ "$_ostype" = "unknown-linux-gnueabihf" ] && [ "$_cputype" = armv7 ]; then
-        if ensure grep '^Features' /proc/cpuinfo | grep -E -q -v 'neon|simd'; then
+        if ! (ensure grep '^Features' /proc/cpuinfo | grep -E -q 'neon|simd') ; then
             # At least one processor does not have NEON (which is asimd on armv8+).
             _cputype=arm
         fi