Fix parsing string parameters in BOARD_MKBOOTIMG_ARGS

The existing logic in common.py breaks string arguments incorrectly:
e.g. --para1 val1 --para2 "val2 is a string" will be output as:

'--para', 'val1, '--para2', 'val2' 'is' 'a' 'string'

This will cause mkbootimg command fails due to the invalid arguments
generated from the wrong parsing.

The patch fixes this issue to get:

'--para', 'val1, '--para2', 'val2 is a string'

Change-Id: Ia34ec357550f11ae9d6adc719d86a0c6a9099fbc
Signed-off-by: Jianxun Zhang <jianxun.zhang@intel.com>
diff --git a/core/Makefile b/core/Makefile
index c5509c6..556fe0d 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1233,7 +1233,7 @@
 ifdef PRODUCT_EXTRA_RECOVERY_KEYS
 	$(hide) echo "extra_recovery_keys=$(PRODUCT_EXTRA_RECOVERY_KEYS)" >> $(zip_root)/META/misc_info.txt
 endif
-	$(hide) echo "mkbootimg_args=$(BOARD_MKBOOTIMG_ARGS)" >> $(zip_root)/META/misc_info.txt
+	$(hide) echo 'mkbootimg_args=$(BOARD_MKBOOTIMG_ARGS)' >> $(zip_root)/META/misc_info.txt
 	$(call generate-userimage-prop-dictionary, $(zip_root)/META/misc_info.txt)
 	@# Zip everything up, preserving symlinks
 	$(hide) (cd $(zip_root) && zip -qry ../$(notdir $@) .)
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 05c2a4a..f179717 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -309,7 +309,7 @@
 
   args = info_dict.get("mkbootimg_args", None)
   if args and args.strip():
-    cmd.extend(args.split())
+    cmd.extend(shlex.split(args))
 
   cmd.extend(["--ramdisk", ramdisk_img.name,
               "--output", img.name])