Fix blank line issues reported by flake8

- E301 expected 1 blank line
- E302 expected 2 blank lines
- E303 too many blank lines
- E305 expected 2 blank lines after class or function definition
- E306 expected 1 blank line before a nested definition

Fixed automatically with autopep8:

  git ls-files | grep py$ | xargs autopep8 --in-place \
    --select E301,E302,E303,E305,E306

Manually fix issues in project.py caused by misuse of block comments.

Change-Id: Iee840fcaff48aae504ddac9c3e76d2acd484f6a9
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/254599
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: David Pursehouse <dpursehouse@collab.net>

subcmds/upload.py

@@ -33,6 +33,7 @@ else:
 
 UNUSUAL_COMMIT_THRESHOLD = 5
 
+
 def _ConfirmManyUploads(multiple_branches=False):
   if multiple_branches:
     print('ATTENTION: One or more branches has an unusually high number '
@@ -44,17 +45,20 @@ def _ConfirmManyUploads(multiple_branches=False):
   answer = input("If you are sure you intend to do this, type 'yes': ").strip()
   return answer == "yes"
 
+
 def _die(fmt, *args):
   msg = fmt % args
   print('error: %s' % msg, file=sys.stderr)
   sys.exit(1)
 
+
 def _SplitEmails(values):
   result = []
   for value in values:
     result.extend([s.strip() for s in value.split(',')])
   return result
 
+
 class Upload(InteractiveCommand):
   common = True
   helpSummary = "Upload changes for code review"