Make ProtectHome tmpfs for aurweb

AURweb's rendercomment script uses python's libgit2 bindings which error
out when it can't read /home/aur/.git due to ProtectHome=true, instead
use ProtectHome=tmpfs.

roles/php-fpm/files/php-fpm@.service

@@ -12,7 +12,9 @@ NoNewPrivileges=true
 ;PrivateNetwork=true
 PrivateDevices=true
 
-ProtectHome=true
+# AURweb's rendercomment script git bindings requires access to /home:
+# failed to stat '/home/aur/.gitconfig
+ProtectHome=tmpfs
 ProtectSystem=full
 InaccessiblePaths=-/var/lib/mysql