Merge ~cjwatson/launchpad:fix-py3-execfile into launchpad:master

[Colin Watson]

lp.scripts.harness: Fix exec() for Python 2

https://code.launchpad.net/~cjwatson/launchpad/+git/launchpad/+merge/402638 switched `lp.scripts.harness` from `execfile()` to `exec()`, but there's a subtlety on Python 2 due to the use of a nested function here. As a result, `bin/harness` failed as follows on Python 2:

    Traceback (most recent call last):
      File "bin/harness", line 5, in <module>
        import lp.scripts.harness
      File ".../lib/lp/scripts/harness.py", line 66
        exec(f.read())
    SyntaxError: unqualified exec is not allowed in function '_get_locals' because it contains a nested function with free variables

Explicitly passing `globals()` avoids this.

[Ioana Lasc (ilasc)]

review: Approve

diff --git a/lib/lp/scripts/harness.py b/lib/lp/scripts/harness.py
index ab3a5c7..12f5b8d 100644
--- a/lib/lp/scripts/harness.py
+++ b/lib/lp/scripts/harness.py
@@ -63,7 +63,7 @@ def _get_locals():
     startup = os.environ.get('PYTHONSTARTUP')
     if startup:
         with open(startup) as f:
-            exec(f.read())
+            exec(f.read(), globals())
     store = IMasterStore(Person)
 
     if dbuser == 'launchpad':