Don't write editable requirements to a temporary file

We never need to read from the file, so it's unnecessary.

pipenv/utils.py

@@ -462,13 +462,12 @@ def actually_resolve_reps(deps, index_lookup, markers_lookup, project, sources,
     constraints = []
 
     for dep in deps:
-        t = tempfile.mkstemp(prefix='pipenv-', suffix='-requirement.txt')[1]
-        with open(t, 'w') as f:
-            f.write(dep)
-
         if dep.startswith('-e '):
             constraint = pip.req.InstallRequirement.from_editable(dep[len('-e '):])
         else:
+            t = tempfile.mkstemp(prefix='pipenv-', suffix='-requirement.txt')[1]
+            with open(t, 'w') as f:
+                f.write(dep)
             constraint = [c for c in pip.req.parse_requirements(t, session=pip._vendor.requests)][0]
 
         if ' -i ' in dep:

tests/test_pipenv.py

@@ -435,6 +435,7 @@ setup(
             assert 'idna' in p.lockfile['default']
             assert 'urllib3' in p.lockfile['default']
             assert 'certifi' in p.lockfile['default']
+            assert os.listdir(p.tmpdir) == []
 
     @pytest.mark.install
     @pytest.mark.pin