[gnome-continuous-yocto/gnomeostree-3.28-rocko: 6433/8267] wic: fix restoring of original fstab

[Emmanuele Bassi <ebassi src gnome org>]

commit 44023e6c41a57d93d7b3a7c6d297e1ca77cd69ff
Author: Ed Bartosh <ed bartosh linux intel com>
Date:   Fri Jun 16 16:19:30 2017 +0300

    wic: fix restoring of original fstab
    
    Wic updates fstab if mount points are specified in .wks.
    After partition images are created the original fstab is restored.
    However, if exception is raised when partition image being prepared
    wic doesn't restore original fstab. This can cause duplication of
    added lines in fstab when 'wic create' runs next time.
    
    Wrapping call of 'prepare' method and restoring original fstab
    even if exception occurs should fix this.
    
    [YOCTO #11633]
    
    (From OE-Core rev: 29f7735030d383f9614bdb148b52a47c79f05eea)
    
    Signed-off-by: Ed Bartosh <ed bartosh linux intel com>
    Signed-off-by: Ross Burton <ross burton intel com>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 scripts/lib/wic/plugins/imager/direct.py |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/scripts/lib/wic/plugins/imager/direct.py b/scripts/lib/wic/plugins/imager/direct.py
index ad9082b..aa9cc9f 100644
--- a/scripts/lib/wic/plugins/imager/direct.py
+++ b/scripts/lib/wic/plugins/imager/direct.py
@@ -172,10 +172,11 @@ class DirectPlugin(ImagerPlugin):
                     if rsize_bb:
                         part.size = int(round(float(rsize_bb)))
 
-        self._image.prepare(self)
-
-        if fstab_path:
-            shutil.move(fstab_path + ".orig", fstab_path)
+        try:
+            self._image.prepare(self)
+        finally:
+            if fstab_path:
+                shutil.move(fstab_path + ".orig", fstab_path)
 
         self._image.layout_partitions()
         self._image.create()