Correct redundant phrase in Getting a Git Repository

"VCS systems" is a redundant acronym phrase (like "ATM machines").

Author: SherryHietala

book/02-git-basics/sections/getting-a-repository.asc

@@ -57,7 +57,7 @@ At this point, you have a Git repository with tracked files and an initial commi
 ==== Cloning an Existing Repository
 
 If you want to get a copy of an existing Git repository -- for example, a project you'd like to contribute to -- the command you need is `git clone`.
-If you're familiar with other VCS systems such as Subversion, you'll notice that the command is "clone" and not "checkout".
+If you're familiar with other VCSs such as Subversion, you'll notice that the command is "clone" and not "checkout".
 This is an important distinction -- instead of getting just a working copy, Git receives a full copy of nearly all data that the server has.
 Every version of every file for the history of the project is pulled down by default when you run `git clone`.
 In fact, if your server disk gets corrupted, you can often use nearly any of the clones on any client to set the server back to the state it was in when it was cloned (you may lose some server-side hooks and such, but all the versioned data would be there -- see <<ch04-git-on-the-server#_getting_git_on_a_server>> for more details).