Fix line parsing in requirements check

The requirements check script would strip one character from the end
of every line without a #, which was a problem if the last line
of the file had neither a # or a newline.

Change-Id: I89f1114695adc4de6ef95a96cffcf919c88a2ac8

modules/jenkins/files/slave_scripts/project-requirements-change.py

@@ -43,7 +43,8 @@ class RequirementsList(object):
         if not os.path.exists(fn):
             return
         for line in open(fn):
-            line = line[:line.find('#')]
+            if '#' in line:
+                line = line[:line.find('#')]
             line = line.strip()
             if (not line or
                 line.startswith('http://tarballs.openstack.org/') or