Clean up init /proc/cmdline handling.

Helped debug a problem where the N9 bootloader incorrectly
concatenated the various command lines.

Bug: http://b/20906691
Change-Id: I0580b06f4185129c7eedf0bdf74b5ce17f88bf9c
diff --git a/init/util.h b/init/util.h
index 6864acf..4ac941e 100644
--- a/init/util.h
+++ b/init/util.h
@@ -58,7 +58,8 @@
 void remove_link(const char *oldpath, const char *newpath);
 int wait_for_file(const char *filename, int timeout);
 void open_devnull_stdio(void);
-void import_kernel_cmdline(bool in_qemu, std::function<void(char*,bool)>);
+void import_kernel_cmdline(bool in_qemu,
+                           std::function<void(const std::string&, const std::string&, bool)>);
 int make_dir(const char *path, mode_t mode);
 int restorecon(const char *pathname);
 int restorecon_recursive(const char *pathname);