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>

pager.py

@@ -27,6 +27,7 @@ pager_process = None
 old_stdout = None
 old_stderr = None
 
+
 def RunPager(globalConfig):
   if not os.isatty(0) or not os.isatty(1):
     return
@@ -39,6 +40,7 @@ def RunPager(globalConfig):
   else:
     _ForkPager(pager)
 
+
 def TerminatePager():
   global pager_process, old_stdout, old_stderr
   if pager_process:
@@ -52,6 +54,7 @@ def TerminatePager():
     sys.stdout = old_stdout
     sys.stderr = old_stderr
 
+
 def _PipePager(pager):
   global pager_process, old_stdout, old_stderr
   assert pager_process is None, "Only one active pager process at a time"
@@ -62,6 +65,7 @@ def _PipePager(pager):
   sys.stdout = pager_process.stdin
   sys.stderr = pager_process.stdin
 
+
 def _ForkPager(pager):
   global active
   # This process turns into the pager; a child it forks will
@@ -88,6 +92,7 @@ def _ForkPager(pager):
     print("fatal: cannot start pager '%s'" % pager, file=sys.stderr)
     sys.exit(255)
 
+
 def _SelectPager(globalConfig):
   try:
     return os.environ['GIT_PAGER']
@@ -105,6 +110,7 @@ def _SelectPager(globalConfig):
 
   return 'less'
 
+
 def _BecomePager(pager):
   # Delaying execution of the pager until we have output
   # ready works around a long-standing bug in popularly