Rename collected logs for easier CI viewing

OpenStack-CI facilitates the ability to view compressed
files on the log server if they have the suffix .txt.gz.

This patch ensures that all collected log files are renamed
to have a .txt suffix before compressing them.

The following changes are also made:
- The bindep file is also cleaned up a little to reduce
  unnecessary duplication.
- PYTHONUNBUFFERED is set to ensure that the console log
  from the CI jobs are in the exact order of execution.

Change-Id: I89f5734275dc2789f44b5bd9c0b45dc34c4a7a50

bindep.txt

@@ -41,5 +41,4 @@ pyOpenSSL                   [platform:rpm]
 python-ndg_httpsclient      [platform:rpm]
 
 # Required for compressing collected log files in CI
-gzip              [platform:dpkg]
-gzip              [platform:rpm]
+gzip

tox.ini

@@ -27,6 +27,7 @@ whitelist_externals =
     wget
 setenv =
     VIRTUAL_ENV={envdir}
+    PYTHONUNBUFFERED=1
 
 
 [testenv:docs]
@@ -186,7 +187,8 @@ commands =
                      && (echo "Idempotence test: pass" && exit 0) \
                      || (echo "Idempotence test: fail" && exit 1)'
     bash -c 'mkdir -p {toxinidir}/logs'
-    bash -c 'rsync -av --ignore-errors /var/log/ /openstack/log/ {toxinidir}/logs/ || true'
+    bash -c 'rsync --archive --verbose --ignore-errors /var/log/ /openstack/log/ {toxinidir}/logs/ || true'
+    bash -c 'find "{toxinidir}/logs/" -type f | sed "p;s|$|.txt|" | xargs -n2 mv'
     bash -c '$(which gzip) --best --recursive "{toxinidir}/logs/"'