Fix l-c and requirements job

- update grpcio in requirements.txt
- update cffi, greenlet and grpcio in l-c to avoid problems
when trying to build the wheels.
- adds .stestr to gitignore

Change-Id: Id2d1c3ea60c33803a35082b9064ccba982b014a7

.gitignore

@@ -53,6 +53,7 @@ ChangeLog
 !/.pylintrc
 !/.testr.conf
 !/.stestr.conf
+.stestr
 
 contrib/vagrant/.vagrant
 

lower-constraints.txt

@@ -5,7 +5,7 @@ appdirs==1.4.3
 Babel==2.5.3
 cachetools==2.0.1
 certifi==2018.1.18
-cffi==1.11.5
+cffi==1.14.0
 chardet==3.0.4
 click==6.7
 cliff==2.11.0
@@ -28,8 +28,8 @@ fixtures==3.0.0
 Flask==0.12.3
 future==0.16.0
 futurist==1.6.0
-greenlet==0.4.13
-grpcio==1.12.0
+greenlet==0.4.16
+grpcio==1.25.0
 idna==2.6
 imagesize==1.0.0
 iso8601==0.1.12

requirements.txt

@@ -22,6 +22,6 @@ PrettyTable>=0.7.2  # BSD
 pyroute2>=0.5.7;sys_platform!='win32' # Apache-2.0 (+ dual licensed GPL2)
 retrying!=1.3.0,>=1.2.3 # Apache-2.0
 stevedore>=1.20.0 # Apache-2.0
-grpcio>=1.12.0 # Apache-2.0
+grpcio>=1.25.0 # Apache-2.0
 protobuf>=3.6.0 # 3-Clause BSD
 prometheus_client>=0.6.0 # Apache-2.0