Partially revert "acbs: treat /tree as a "safe directory""

The installation part should be handled by Ciel (while configuring Ciel
containers), not ACBS. ACBS still passes safe.directory option to Git
command line.
This reverts commit 21a8784.

acbs/main.py

@@ -24,7 +24,6 @@
     ACBSLogFormatter,
     ACBSLogPlainFormatter,
     check_artifact,
-    detect_nspawn,
     full_line_banner,
     generate_checksums,
     guess_subdir,
@@ -41,12 +40,6 @@
 
 CIEL_LOCK_PATH = '/debs/fresh.lock'
 
-# Git config to treat the ABBS tree as "safe directory".
-GIT_CONFIG_SAFEDIR = """
-[safe]
-\tdirectory = /tree
-"""
-
 def ciel_invalidate_cache():
     logging.info('Asking ciel to refresh repository...')
     if os.path.exists(CIEL_LOCK_PATH):
@@ -156,14 +149,6 @@ def init(self) -> None:
             else:
                 raise Exception('forest.conf not found')
 
-        # Install a git config file to allow dubious ownership in /tree.
-        if detect_nspawn():
-            try:
-                with open("/root/.gitconfig", 'w+') as f:
-                    f.writelines(GIT_CONFIG_SAFEDIR)
-            except Exception as e:
-                logging.warning("Unable to install git config file: {}, skipping.".format(e))
-
     def __install_logger(self, str_verbosity=logging.INFO,
                          file_verbosity=logging.DEBUG):
         logger = logging.getLogger()

acbs/utils.py

@@ -438,16 +438,3 @@ def format(self, record):
                               logging.INFO, logging.DEBUG):
             record.msg = f'[{lvl_map[record.levelname]}]: {record.msg}'
         return super(ACBSLogFormatter, self).format(record)
-
-def detect_nspawn() -> bool:
-    try:
-        with open("/run/systemd/container", "r") as f:
-            content = f.readline()
-            if content.strip() == "systemd-nspawn":
-                return True
-    except FileNotFoundError:
-        return False
-    except Exception as e:
-        logging.warning("Unable to detect containerization: {}, assuming false.".format(e))
-        return False
-    return False