llvm_tools: Make skip_dependencies optional

This CL makes new skip_denedencies arg in get_upstream patch default to
False so that the new behavior introduced in CL:3255665 is disabled by
default. This is intended to fix a failure in the nightly revert checker
that was preventing cherry_picks.

BUG=b:206461485
TEST=Local test of get_upstream_patch.py, and
nightly_revert_checker_test.py

Change-Id: Ia7586b69f9aefb5ca820a60eed593d45a4b9a5bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/3282951
Reviewed-by: Christopher Di Bella <cjdb@google.com>
Commit-Queue: Christopher Di Bella <cjdb@google.com>
Tested-by: Christopher Di Bella <cjdb@google.com>
Auto-Submit: Ryan Beltran <ryanbeltran@chromium.org>
diff --git a/llvm_tools/get_upstream_patch.py b/llvm_tools/get_upstream_patch.py
index cc5505d..f72891e 100755
--- a/llvm_tools/get_upstream_patch.py
+++ b/llvm_tools/get_upstream_patch.py
@@ -280,9 +280,9 @@
 
 def get_from_upstream(chroot_path: str,
                       create_cl: bool,
-                      skip_dependencies: bool,
                       start_sha: str,
                       patches: t.List[str],
+                      skip_dependencies: bool = False,
                       reviewers: t.List[str] = None,
                       cc: t.List[str] = None):
   llvm_symlink = chroot.ConvertChrootPathsToAbsolutePaths(
@@ -361,11 +361,13 @@
     parser.error("--skip_dependencies is only valid when there's exactly one "
                  'supplied differential')
 
-  get_from_upstream(chroot_path=args.chroot_path,
-                    create_cl=args.create_cl,
-                    skip_dependencies=args.skip_dependencies,
-                    start_sha=args.start_sha,
-                    patches=args.sha + args.differential)
+  get_from_upstream(
+      chroot_path=args.chroot_path,
+      create_cl=args.create_cl,
+      start_sha=args.start_sha,
+      patches=args.sha + args.differential,
+      skip_dependencies=args.skip_dependencies,
+  )
 
 
 if __name__ == '__main__':