Line-wrap projects.yaml but strip trailing spaces

This restores ruamel's new line-wrapping behavior, but corrects the
trailing spaces that it leaves by stripping them in our customized
output routine.

Change-Id: I795994657abb3d706c2a0725c5955e15e5c067ba

tools/projectconfig_ruamellib.py

@@ -13,8 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import sys
-
 import ruamel.yaml
 
 
@@ -29,9 +27,6 @@ class YAML(object):
         self.yaml.allow_duplicate_keys = True
         self.yaml.representer.add_representer(type(None), none_representer)
         self.yaml.indent(mapping=2, sequence=4, offset=2)
-        # Ruamel does weird things with linewrapping like adding extra
-        # whitespace at the end of lines. Just avoid wrapping entirely.
-        self.yaml.width = sys.maxsize
 
     def load(self, stream):
         return self.yaml.load(stream)
@@ -41,9 +36,9 @@ class YAML(object):
         newlines = []
         for line in x.split('\n'):
             if '#' in line:
-                newlines.append(line)
+                newlines.append(line.rstrip())
             else:
-                newlines.append(line[2:])
+                newlines.append(line[2:].rstrip())
         return '\n'.join(newlines)
 
     def dump(self, data, *args, **kwargs):