Add debug logging to eden chown

Summary:
# Context
test_chown_with_bindmount is failing on test runners, but not locally.  https://www.internalfb.com/intern/test/562950217315212?ref_report_id=0

Print out the results of calling sudo chown to help debug.

My suspicion is that there might be limited sudo on the test runner, and this will help confirm that.

eg. This test fails on ondemands. Sudo will return the following error, which was previously silent.

```
##
## IMPORTANT!
##
## On Demand instances have very limited 'sudo' access.
##
##  * Run 'sudo -l' to see the list of commands you can run.
##
##  * If a password prompt appears, press Ctrl+C to cancel. Your
##    password will NOT work at this prompt. This means On Demand
##    does not allow running that command via sudo.
##
## For more information, see https://fburl.com/ondemandsudo
```

Reviewed By: vilatto

Differential Revision: D91076412

fbshipit-source-id: f1983e9394acec8e2ecf824325a523981adc8e89

Author: Alramech

eden/fs/cli/main.py

@@ -1432,6 +1432,12 @@ def setup_parser(self, parser: argparse.ArgumentParser) -> None:
             default=False,
             help="Are redirections also chowned",
         )
+        parser.add_argument(
+            "--verbose",
+            action="store_true",
+            default=False,
+            help="Add more info to the output, such as the output of the chown sub-calls",
+        )
 
     def resolve_uid(self, uid_str: str) -> int:
         try:
@@ -1472,15 +1478,37 @@ def run(self, args: argparse.Namespace) -> int:
             ).values():
                 target = redir.expand_target_abspath(checkout)
                 print(f"Chowning redirection: {redir.repo_path}...", end="", flush=True)
-                subprocess.run(["sudo", "chown", "-R", f"{uid}:{gid}", str(target)])
-                subprocess.run(
+                result1 = subprocess.run(
+                    ["sudo", "chown", "-R", f"{uid}:{gid}", str(target)],
+                    capture_output=True,
+                    text=True,
+                )
+                if args.verbose:
+                    print(f"\nChowning target: {str(target)}")
+                    print("stdout:")
+                    print(result1.stdout)
+                    if result1.stderr:
+                        print("stderr: ")
+                        print(result1.stderr)
+
+                result2 = subprocess.run(
                     [
                         "sudo",
                         "chown",
                         f"{uid}:{gid}",
                         str(checkout.path / redir.repo_path),
-                    ]
+                    ],
+                    capture_output=True,
+                    text=True,
                 )
+                if args.verbose:
+                    print(f"Chowning repo path: {checkout.path / redir.repo_path}")
+                    print("stdout:")
+                    print(result2.stdout)
+                    if result2.stderr:
+                        print("stderr:")
+                        print(result2.stderr)
+
                 print("done")
 
         return 0

eden/integration/chown_test.py

@@ -78,10 +78,10 @@ def assert_chown_worked(self, mount: str) -> None:
     def run_chown(self, mount: str, use_ids: bool = False) -> None:
         if use_ids:
             output = self.eden.run_cmd(
-                "chown", mount, str(self.nobody_uid), str(self.nobody_gid)
+                "chown", mount, str(self.nobody_uid), str(self.nobody_gid), "--verbose"
             )
         else:
-            output = self.eden.run_cmd("chown", mount, "nobody", "nobody")
+            output = self.eden.run_cmd("chown", mount, "nobody", "nobody", "--verbose")
         print(output)
 
     def test_chown(self) -> None: