Don't fail when trying to detect OS architecture on RPM-based systems

Signed-off-by: DL6ER <dl6er@dl6er.de>

automated install/basic-install.sh

@@ -2294,10 +2294,12 @@ get_binary_name() {
     elif [[ "${machine}" == "x86_64" ]]; then
         # This gives the architecture of packages dpkg installs (for example, "i386")
         local dpkgarch
-        dpkgarch=$(dpkg --print-architecture 2> /dev/null)
+        dpkgarch=$(dpkg --print-architecture 2> /dev/null || true)
 
         # Special case: This is a 32 bit OS, installed on a 64 bit machine
         # -> change machine architecture to download the 32 bit executable
+        # We only check this for Debian-based systems as this has been an issue
+        # in the past (see https://github.com/pi-hole/pi-hole/pull/2004)
         if [[ "${dpkgarch}" == "i386" ]]; then
             printf "%b  %b Detected 32bit (i686) architecture\\n" "${OVER}" "${TICK}"
             binary="pihole-FTL-linux-x86_32"