[lldb][NFC] Give added test method a unique name

Otherwise dotest doesn't run the test and just lets it always pass.
Also update the comment to explain that we do directory and not
file completion.

llvm-svn: 370047

Author: Teemperor

lldb/packages/Python/lldbsuite/test/functionalities/completion/TestCompletion.py

@@ -138,8 +138,8 @@ def test_log_file(self):
                               ['main.cpp'])
 
     @skipIfFreeBSD  # timing out on the FreeBSD buildbot
-    def test_log_file(self):
-        # Complete in our source directory which contains a 'main.cpp' file.
+    def test_log_dir(self):
+        # Complete our source directory.
         src_dir =  os.path.dirname(os.path.realpath(__file__))
         self.complete_from_to('log enable lldb expr -f ' + src_dir,
                               [src_dir + "/"])