canned_fs_config.cpp is written in C++

This re-writes the file using C++, in preparation for a follow-up
change.

Also, removes debugging code that is no longer used.

Bug: 209971551
Test: m
Change-Id: I82a793cfdd7abd10024e304df7bd4ae323ffeabf
diff --git a/libcutils/Android.bp b/libcutils/Android.bp
index 0d9f2c7..c8bfb01 100644
--- a/libcutils/Android.bp
+++ b/libcutils/Android.bp
@@ -156,7 +156,6 @@
     },
     srcs: [
         "config_utils.cpp",
-        "canned_fs_config.cpp",
         "iosched_policy.cpp",
         "load_file.cpp",
         "native_handle.cpp",
@@ -173,6 +172,7 @@
         not_windows: {
             srcs: libcutils_nonwindows_sources + [
                 "ashmem-host.cpp",
+                "canned_fs_config.cpp",
                 "fs_config.cpp",
                 "trace-host.cpp",
             ],
@@ -193,6 +193,7 @@
             srcs: libcutils_nonwindows_sources + [
                 "android_reboot.cpp",
                 "ashmem-dev.cpp",
+                "canned_fs_config.cpp",
                 "fs_config.cpp",
                 "klog.cpp",
                 "partition_utils.cpp",