qemu-iotests: Fix FilePaths docstring

When this class was extracted from FilePath, the docstring was not
updated for generating multiple files, and the example usage was
referencing unrelated file.

While fixing the docstring, add example for creating sockets, which
should use iotests.sock_dir instead of the default base_dir.

Fixes: de263986b5
Signed-off-by: Nir Soffer <nsoffer@redhat.com>
Message-Id: <20200828232152.205833-3-nsoffer@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

tests/qemu-iotests/iotests.py

@@ -450,14 +450,21 @@ def file_pattern(name):
 
 class FilePaths:
     """
-    FilePaths is an auto-generated filename that cleans itself up.
+    Context manager generating multiple file names. The generated files are
+    removed when exiting the context.
 
-    Use this context manager to generate filenames and ensure that the file
-    gets deleted::
+    Example usage:
+
+        with FilePaths(['a.img', 'b.img']) as (img_a, img_b):
+            # Use img_a and img_b here...
+
+        # a.img and b.img are automatically removed here.
+
+    By default images are created in iotests.test_dir. To create sockets use
+    iotests.sock_dir:
+
+       with FilePaths(['a.sock'], base_dir=iotests.sock_dir) as (sock,):
 
-        with FilePaths(['test.img']) as img_path:
-            qemu_img('create', img_path, '1G')
-        # migration_sock_path is automatically deleted
     """
     def __init__(self, names, base_dir=test_dir):
         self.paths = []