change xrange() to range()

Python 3 doesn't support xrange, so convert all the usage to range.
This is mostly mechanical, but the conversion tripped a few new
warnings with consider-using-enumerate.

BUG=chromium:980619
TEST=lint is unchanged in chromite
TEST=unittests pass

Change-Id: I9f99e323c3d6d993f40b544cabfcc8697d105f47
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1689012
Tested-by: Mike Frysinger <vapier@chromium.org>
Auto-Submit: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Ned Nguyen <nednguyen@google.com>
Reviewed-by: David Burger <dburger@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/parallel_emerge.py b/scripts/parallel_emerge.py
index 27e9d3d..1c80e44 100644
--- a/scripts/parallel_emerge.py
+++ b/scripts/parallel_emerge.py
@@ -686,7 +686,7 @@
           if dep in unresolved:
             idx = unresolved.index(dep)
             mycycle = unresolved[idx:] + [dep]
-            for i in xrange(len(mycycle) - 1):
+            for i in range(len(mycycle) - 1):
               pkg1, pkg2 = mycycle[i], mycycle[i+1]
               cycles.setdefault(pkg1, {}).setdefault(pkg2, mycycle)
           elif not pkg_cycles or dep not in pkg_cycles:
@@ -744,7 +744,7 @@
       print("Breaking %s -> %s (%s)" % (dep, basedep, depinfo))
 
       # Show cycle.
-      for i in xrange(len(mycycle) - 1):
+      for i in range(len(mycycle) - 1):
         pkg1, pkg2 = mycycle[i], mycycle[i+1]
         needs = deps_map[pkg1]["needs"]
         depinfo = needs.get(pkg2, "deleted")
@@ -1724,7 +1724,7 @@
       return
 
     # Start the fetchers.
-    for _ in xrange(min(self._fetch_procs, len(self._fetch_ready))):
+    for _ in range(min(self._fetch_procs, len(self._fetch_ready))):
       state = self._fetch_ready.get()
       self._fetch_jobs[state.target] = None
       self._fetch_queue.put(state)
@@ -1761,7 +1761,7 @@
             print("Deadlock! Circular dependencies!")
           sys.exit(1)
 
-      for _ in xrange(12):
+      for _ in range(12):
         try:
           job = self._job_queue.get(timeout=5)
           break