bullseye: Rename misleading dry-run option

The previous `--dry-run` actually means that bullseye will abandon the
target branch in the end. "Dry run" suggests that it won't touch the
tree, so rename this option into `--cleanup-after`.

Change-Id: I5d24386e59bad40e6232200e4822ab51e75ca880
diff --git a/bullseye/bulletin.py b/bullseye/bulletin.py
index a9f3d13..632c1d8 100644
--- a/bullseye/bulletin.py
+++ b/bullseye/bulletin.py
@@ -90,7 +90,7 @@
 
         if not self.is_applied():
             print("[BE]: Not yet applied: {}".format(self.get_description()))
-            if self.args.apply_to_branch is not None:
+            if self.args.apply_to_branch:
                 self.apply()
         else:
             print("[BE]: Already applied: {}".format(self.get_description()))
@@ -162,7 +162,7 @@
             self.rollback()
         else:
             print("[BE]:    SUCCESS: applied.".format(self.filename))
-            if not self.args.skip_amend and not self.args.dry_run:
+            if not self.args.skip_amend and not self.args.cleanup_after:
                 self.amend()
 
     def exec_command(self, command):
diff --git a/bullseye/bullseye.py b/bullseye/bullseye.py
index a8901ff..4230304 100755
--- a/bullseye/bullseye.py
+++ b/bullseye/bullseye.py
@@ -30,8 +30,10 @@
         "--apply-to-branch",
         type=str,
         help="Branch to apply patches to, if this option is set patches will "
-        "be applied to this branch. WARNING: This branch will abandoned if it "
-        "exists already.",
+        "be applied to this branch. Not setting this effectively results in a "
+        "dry run. No changes will be made in the tree.\n"
+        "WARNING: The branch set here will be abandoned if it already exists "
+        "and --skip-abandon is not set.",
     )
     parser.add_argument(
         "--use-a-number",
@@ -44,9 +46,10 @@
         help="Display both the A-number and the patch path",
     )
     parser.add_argument(
-        "--dry-run",
+        "--cleanup-after",
         action="store_true",
-        help="Do rollback after applying the patch",
+        help="Abandon the branch selected in --apply-to-branch after bullseye "
+        "is done. This implies --skip-amend.",
     )
     parser.add_argument(
         "--skip-amend", action="store_true", help="Skip amend step"
@@ -54,7 +57,8 @@
     parser.add_argument(
         "--skip-abandon",
         action="store_true",
-        help="Skip abandoning the target repo branch",
+        help="Skip the default behavior of abandoning and recreating the "
+        "target repo branch before applying any patches.",
     )
     parser.add_argument(
         "--skip-patches", action="store_true", help="Skip the bulletin patches"
@@ -67,7 +71,7 @@
     parser.add_argument(
         "--quiet",
         action="store_true",
-        help="Be a bit quieter. (Surpress git output)",
+        help="Be a bit quieter. (Suppress git output)",
     )
     parser.add_argument(
         "--use-old-format",
@@ -100,6 +104,17 @@
 if __name__ == "__main__":
     parser = make_arg_parser()
     args = parser.parse_args()
+    if not args.apply_to_branch:
+        print(
+            "INFO: This is a dry run, because --apply-to-branch is not "
+            "specified."
+        )
+        if args.cleanup_after:
+            print(
+                "WARNING: Argument --cleanup-after will be ignored, because"
+                "--apply-to-branch is not specified."
+            )
+
     manifest = AndroidManifest(
         os.path.join(args.aosp_root, ".repo", "manifest.xml")
     )
@@ -109,6 +124,6 @@
     bulletin = SecurityBulletin(args, manifest)
     bulletin.apply()
 
-    if args.dry_run:
-        print("Was dry run ...rolling back.")
+    if args.cleanup_after and args.apply_to_branch:
+        print("Abandoning the target branch as requested.")
         rollback()