fs_mgr: Drop the context mount option from non-selinux builds

Transitioning devices may have the context option present in the
fstab, even if we're not doing selinux builds.
Since we don't set or even create the contexts on those builds,
this will make mount fail, and either the mountpoint ends up absent,
or boot fails entirely

Change-Id: Ic5cc7f5632cc3d62459dfaaf7719d662737e1641

fs_mgr/Android.mk

@@ -3,6 +3,10 @@
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
+ifeq ($(HAVE_SELINUX),true)
+LOCAL_CFLAGS += -DHAVE_SELINUX
+endif
+
 LOCAL_SRC_FILES:= fs_mgr.c
 
 LOCAL_C_INCLUDES := $(LOCAL_PATH)/include

fs_mgr/fs_mgr.c

@@ -147,8 +147,14 @@ static int parse_flags(char *flags, struct flag_list *fl, char **key_loc,
                 /* It's not a known flag, so it must be a filesystem specific
                  * option.  Add it to fs_options if it was passed in.
                  */
-                strlcat(fs_options, p, fs_options_len);
-                strlcat(fs_options, ",", fs_options_len);
+#ifndef HAVE_SELINUX
+                /* Drop context option from non-selinux builds */
+                if (strncmp(p,"context=",8))
+#endif
+                {
+                    strlcat(fs_options, p, fs_options_len);
+                    strlcat(fs_options, ",", fs_options_len);
+                }
             } else {
                 /* fs_options was not passed in, so if the flag is unknown
                  * it's an error.