Be more liberal in accepting Signed-off-by lines

Android kernel team sometimes needs to cherry-pick patches from the
mainline kernel, patches that have already been Signed-off-by the
author and Linus Torvalds.  In such cases requiring that the Android
developer add their own Signed-off-by line to an already existing
commit from mainline is rather useless, so we relax the requirement.

Requested-by: Brian Swetland <swetland@google.com>
Signed-off-by: Shawn O. Pearce <sop@google.com>

src/main/java/com/google/gerrit/server/ssh/commands/Receive.java

diff --git a/src/main/java/com/google/gerrit/server/ssh/commands/Receive.java b/src/main/java/com/google/gerrit/server/ssh/commands/Receive.java
index a62b49c..37c2e62 100644
--- a/src/main/java/com/google/gerrit/server/ssh/commands/Receive.java
+++ b/src/main/java/com/google/gerrit/server/ssh/commands/Receive.java
@@ -1075,12 +1075,8 @@
           }
         }
       }
-      if (!sboMe) {
-        reject(cmd, "not Signed-off-by you");
-        return false;
-      }
-      if (!sboCommitter) {
-        reject(cmd, "not Signed-off-by " + committer.getEmailAddress());
+      if (!sboAuthor && !sboCommitter && !sboMe) {
+        reject(cmd, "not Signed-off-by author/committer/uploader");
         return false;
       }
     }