utils: rename ogExtendFs to extend_filesystem

Use a more consistent name format for the ogExtendFs function.

src/live/ogOperations.py

@@ -572,7 +572,7 @@ class OgLiveOperations:
             logging.info(f'partclone process exited with code {p1.returncode}')
             logging.info(f'lzop process exited with code {p2.returncode}')
 
-            ogExtendFs(disk, partition)
+            extend_filesystem(disk, partition)
 
             if os.access(f'{image_path}', os.R_OK) == False:
                 raise OgError(f'Cannot access partclone image file {image_path}')

src/utils/fs.py

@@ -117,7 +117,7 @@ def ogReduceFs(disk, part):
 
     return ret
 
-def ogExtendFs(disk, part):
+def extend_filesystem(disk, part):
     """
     Grow filesystem of a partition. Supports ext4 and ntfs partitions.
     Unsupported filesystem or invalid paths don't raise an exception,