Always use repo as reference to JGit repo

Was simplified to `r`

Author: zigarn

book/B-embedding-git/sections/jgit.asc

@@ -69,21 +69,21 @@ ObjectId masterTip = master.getObjectId();
 ObjectId obj = repo.resolve("HEAD^{tree}");
 
 // Load raw object contents
-ObjectLoader loader = r.open(masterTip);
+ObjectLoader loader = repo.open(masterTip);
 loader.copyTo(System.out);
 
 // Create a branch
-RefUpdate createBranch1 = r.updateRef("refs/heads/branch1");
+RefUpdate createBranch1 = repo.updateRef("refs/heads/branch1");
 createBranch1.setNewObjectId(masterTip);
 createBranch1.update();
 
 // Delete a branch
-RefUpdate deleteBranch1 = r.updateRef("refs/heads/branch1");
+RefUpdate deleteBranch1 = repo.updateRef("refs/heads/branch1");
 deleteBranch1.setForceUpdate(true);
 deleteBranch1.delete();
 
 // Config
-Config cfg = r.getConfig();
+Config cfg = repo.getConfig();
 String name = cfg.getString("user", null, "name");
 ----