Sync tools/tox_install.sh with python-openstackclient. This brings in
the following improvements:
* Do not leave temporary directory around, instead delete temporary
directory directly after usage (change
I939eae82dba3287fd4e4086128ebf4609a0e0770).
* Do not set ZUUL_BRANCH explicitely and remove unused if condition
(change I0077c986a17d6bb92791474e03d1e77776e9382f).
Change-Id: I2415468b703e608c81c51bfa25126f7e8d204a00
This review is to prepare for adding monasca-common into openstack
global-requirements. After this project gets into global requirements,
it will be in upper-constraints.txt. If we make changes on this
specific project, we need to replace it in the upper-constraints with
source based specifier before applying it to pip install.
Change-Id: I67a3e3fcb833e273900c490643197988efd5eb3b
