Merge pull request #2072 from wojiushixiaobai/docs

[Update]更新

docs/step_by_step.rst

@@ -422,16 +422,15 @@ Guacamole 需要 Tomcat 来运行
 
 .. code-block:: shell
 
+    $ mkdir /usr/local/lib/freerdp/
+    $ ln -s /usr/local/lib/freerdp /usr/lib64/freerdp
     $ rpm --import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro
     $ rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-5.el7.nux.noarch.rpm
     $ yum -y localinstall --nogpgcheck https://download1.rpmfusion.org/free/el/rpmfusion-free-release-7.noarch.rpm https://download1.rpmfusion.org/nonfree/el/rpmfusion-nonfree-release-7.noarch.rpm
 
     $ yum install -y java-1.8.0-openjdk libtool
     $ yum install -y cairo-devel libjpeg-turbo-devel libpng-devel uuid-devel
-    $ yum install -y ffmpeg-devel freerdp-devel pango-devel libssh2-devel libtelnet-devel libvncserver-devel pulseaudio-libs-devel openssl-devel libvorbis-devel libwebp-devel ghostscript
-
-    $ mkdir /usr/local/lib/freerdp/
-    $ ln -s /usr/local/lib/freerdp /usr/lib64/freerdp
+    $ yum install -y ffmpeg-devel freerdp-devel freerdp-plugins pango-devel libssh2-devel libtelnet-devel libvncserver-devel pulseaudio-libs-devel openssl-devel libvorbis-devel libwebp-devel ghostscript
 
 **5.2 编译安装 guacamole 服务**