Remove monotonic usage

The monotonic package was needed for monotonic time operations when
running under Python runtimes older than 3.3. Since we now only support
versions higher than this, this third party package requirement can now
be removed.

Change-Id: Id250b92d11aeb6fa02e264610bfe8e8c71df7e26
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

lower-constraints.txt

@@ -22,7 +22,6 @@ keystoneauth1==3.4.0
 linecache2==1.0.0
 MarkupSafe==1.0
 mccabe==0.2.1
-monotonic==1.4;python_version<'3.3'
 mox3==0.25.0
 msgpack==0.5.6
 netaddr==0.7.19

oslo_log/rate_limit.py

@@ -14,11 +14,7 @@
 
 
 import logging
-
-try:
-    from time import monotonic as monotonic_clock   # noqa
-except ImportError:
-    from monotonic import monotonic as monotonic_clock   # noqa
+from time import monotonic as monotonic_clock
 
 
 class _LogRateLimit(logging.Filter):

requirements.txt

@@ -11,4 +11,3 @@ oslo.serialization>=2.25.0 # Apache-2.0
 debtcollector>=1.19.0 # Apache-2.0
 pyinotify>=0.9.6;sys_platform!='win32' and sys_platform!='darwin' and sys_platform!='sunos5' # MIT
 python-dateutil>=2.7.0 # BSD
-monotonic>=1.4;python_version<'3.3' # Apache-2.0