wic: get rid of set_size and set_source_file setters

Used size and source_file attributes instead of using
setters. It's more pythonic, clear an consistent.

(From OE-Core rev: 7cf236047fa5d0d947fd214181c9a63ccb2509ac)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/wic/plugins/source/bootimg-efi.py

@@ -235,5 +235,5 @@ class BootimgEFIPlugin(SourcePlugin):
         out = exec_cmd(du_cmd)
         bootimg_size = out.split()[0]
 
-        part.set_size(bootimg_size)
-        part.set_source_file(bootimg)
+        part.size = bootimg_size
+        part.source_file = bootimg

scripts/lib/wic/plugins/source/bootimg-pcbios.py

@@ -205,7 +205,7 @@ class BootimgPcbiosPlugin(SourcePlugin):
         out = exec_cmd(du_cmd)
         bootimg_size = out.split()[0]
 
-        part.set_size(bootimg_size)
-        part.set_source_file(bootimg)
+        part.size = int(out.split()[0])
+        part.source_file = bootimg
 
 

scripts/lib/wic/plugins/source/isoimage-isohybrid.py

@@ -302,7 +302,7 @@ class IsoImagePlugin(SourcePlugin):
             # which contains rootfs
             du_cmd = "du -bks %s" % rootfs_dir
             out = exec_cmd(du_cmd)
-            part.set_size(int(out.split()[0]))
+            part.size = int(out.split()[0])
             part.extra_space = 0
             part.overhead_factor = 1.2
             part.prepare_rootfs(cr_workdir, oe_builddir, rootfs_dir, \
@@ -502,8 +502,8 @@ class IsoImagePlugin(SourcePlugin):
         out = exec_cmd(du_cmd)
         isoimg_size = int(out.split()[0])
 
-        part.set_size(isoimg_size)
-        part.set_source_file(iso_img)
+        part.size = isoimg_size
+        part.source_file = iso_img
 
     @classmethod
     def do_install_disk(cls, disk, disk_name, creator, workdir, oe_builddir,