Remove unavailable package from General dependencies for CentOS / RHEL

Running-Mastodon/Production-guide.md

@@ -133,7 +133,7 @@ home can be changed as needed
 
 ### CentOS / RHEL
 
-    sudo yum install libxml2-devel ImageMagick libxslt-devel git curl file g++ protobuf-compiler protobuf-devel
+    sudo yum install libxml2-devel ImageMagick libxslt-devel git curl file protobuf-compiler protobuf-devel
     sudo yum -y install epel-release
     sudo rpm --import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro
     sudo rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-5.el7.nux.noarch.rpm