updated pinning to prevent breaking changes (#4783)

* updated ansible pinning to prevent more possibilities of breaking changes

* more exact pinning of ansible version

* more exact pinning of ansible version and also all the rest

* added testing requirements.txt pinning settings

* removed boto from testing requirements.txt

requirements.txt

-ansible>=2.7.8
-jinja2>=2.9.6
-netaddr
-pbr>=1.6
-hvac
-jmespath
-ruamel.yaml
+ansible==2.7.8
+jinja2==2.10.1
+netaddr==0.7.19
+pbr==5.2.0
+hvac==0.8.2
+jmespath==0.9.4
+ruamel.yaml==0.15.96

tests/requirements.txt

 -r ../requirements.txt
-yamllint
+yamllint==1.15.0
 apache-libcloud==2.2.1
-boto==2.9.0
-tox
-dopy
-PyCrypto
+tox==3.11.1
+dopy==0.3.7
+PyCrypto==2.6.1
 ansible-lint==4.1.0
-openshift
+openshift==0.8.8