scripts: Adopted del to resolve shadowed builtins

So:

  all_ = all; del all

Instead of:

  import builtins
  all_, all = all, builtins.all

The del exposes the globally scoped builtin we accidentally shadow.

This requires less megic, and no module imports, though tbh I'm
surprised it works.

It also works in the case where you change a builtin globally, but
that's a bit too crazy even for me...

scripts/dbglfs.py

@@ -3345,8 +3345,7 @@ class Lfs:
     # lookup operations 
     def lookup(self, mid, mdir=None, *,
             all=False):
-        import builtins
-        all_, all = all, builtins.all
+        all_ = all; del all
 
         # is this mid grmed?
         if not all_ and self.grmed(mid):
@@ -3367,8 +3366,7 @@ class Lfs:
 
     def namelookup(self, did, name, *,
             all=False):
-        import builtins
-        all_, all = all, builtins.all
+        all_ = all; del all
 
         mid_, mdir_, name_ = self.mtree.namelookup(did, name)
         if mid_ is None:
@@ -3430,8 +3428,7 @@ class Lfs:
             all=False,
             path=False,
             depth=None):
-        import builtins
-        all_, all = all, builtins.all
+        all_ = all; del all
 
         # default to the root directory
         if path_ is None:
@@ -3470,8 +3467,7 @@ class Lfs:
             all=False,
             path=False,
             depth=None):
-        import builtins
-        all_, all = all, builtins.all
+        all_ = all; del all
 
         file, *path__ = self.pathlookup_(did, path_,
                 all=all_,
@@ -3486,8 +3482,7 @@ class Lfs:
             all=False,
             path=False,
             depth=None):
-        import builtins
-        all_, all = all, builtins.all
+        all_ = all; del all
 
         # default to the root directory
         did = did or self.root.did
@@ -3536,8 +3531,7 @@ class Lfs:
             all=False,
             path=False,
             depth=None):
-        import builtins
-        all_, all = all, builtins.all
+        all_ = all; del all
 
         for file, *path__ in self.files_(did,
                 all=all_,
@@ -3553,8 +3547,7 @@ class Lfs:
 
     def orphans(self,
             all=False):
-        import builtins
-        all_, all = all, builtins.all
+        all_ = all; del all
 
         # first find all reachable dids
         dids = {self.root.did}
@@ -4069,8 +4062,7 @@ def dbg_files(lfs, paths,
         all=False,
         no_orphans=False,
         **args):
-    import builtins
-    all_, all = all, builtins.all
+    all_ = all; del all
 
     # parse all paths first, error if anything is malformed
     dirs = []