Remove dead isGerrit method from AbstractGitCommand

We no longer rely on this to enable extension options, they
are always enabled ever since we moved to args4j.

Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/src/main/java/com/google/gerrit/server/ssh/AbstractGitCommand.java b/src/main/java/com/google/gerrit/server/ssh/AbstractGitCommand.java
index 1dc3859..4106ea76 100644
--- a/src/main/java/com/google/gerrit/server/ssh/AbstractGitCommand.java
+++ b/src/main/java/com/google/gerrit/server/ssh/AbstractGitCommand.java
@@ -36,10 +36,6 @@
   protected Project proj;
   protected Account userAccount;
 
-  protected boolean isGerrit() {
-    return getName().startsWith("gerrit-");
-  }
-
   @Override
   protected void preRun() throws Failure {
     super.preRun();