init: use init's property expansion code for setprop/write

Change-Id: I3c284860cc8d5106ac2b086e62baeb6263873935
Signed-off-by: Dima Zavin <dima@android.com>
diff --git a/init/init_parser.c b/init/init_parser.c
index 311aaea..d255db9 100644
--- a/init/init_parser.c
+++ b/init/init_parser.c
@@ -176,7 +176,7 @@
     return 0;
 }
 
-static int expand_props(char *dst, const char *src, int dst_size)
+int expand_props(char *dst, const char *src, int dst_size)
 {
     int cnt = 0;
     char *dst_ptr = dst;