Merge ~mwhudson/utah/+git/utah:use-communicate into utah:master

[Michael Hudson-Doyle]

use Popen.communicate in ProcessRunnner

Probably ProcessRunnner could be done away with entirely but the
existing implementation didn't always collect _all_ of the subprocess'
output, which is a problem if you're trying to interpret it as JSON.

Yes I was very angry when I wrote this, why do you ask?

[Paride Legovini (paride)]

LGTM

review: Approve

diff --git a/utah/process.py b/utah/process.py
index ef56bbf..705b25b 100644
--- a/utah/process.py
+++ b/utah/process.py
@@ -125,11 +125,7 @@ class ProcessRunner(object):
         logging.debug('Output follows:')
         p = subprocess.Popen(arglist,
                              stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
-        output = []
-        while p.poll() is None:
-            line = p.stdout.readline().strip()
-            logging.debug(line)
-            output.append(line)
+        stdout, stderr = p.communicate()
 
         if p.returncode == 0:
             logging.debug('Return code: {}'.format(p.returncode))
@@ -137,7 +133,7 @@ class ProcessRunner(object):
             logging.warning('Command ({}) failed with return code: {}'
                             .format(' '.join(arglist), p.returncode))
 
-        self.output = '\n'.join(output)
+        self.output = stdout
         self.returncode = p.returncode