init: Enable ANDROID_BASE_UNIQUE_FD_DISABLE_IMPLICIT_CONVERSION

From the unique_fd.h header file: "unique_fd's operator int is
dangerous, but we have way too much code that depends on it, so make
this opt-in at first."

From the Google C++ style guide: "Do not define implicit conversions."
See also go/cstyle#Implicit_Conversions.

Hence this CL that disables unique_fd::operator int().

Change-Id: I28d94755d5408f63e5819da8d1cbc285057f867f
Signed-off-by: Bart Van Assche <bvanassche@google.com>
diff --git a/init/selinux.cpp b/init/selinux.cpp
index ab5b0a0..ea308aa 100644
--- a/init/selinux.cpp
+++ b/init/selinux.cpp
@@ -567,7 +567,7 @@
         return ErrnoError() << "Failed to open " << dstPath;
     }
 
-    ret = ExtractEntryToFile(archive, &entry, fd);
+    ret = ExtractEntryToFile(archive, &entry, fd.get());
     if (ret != 0) {
         return Error() << "Failed to extract entry \"" << fileName << "\" ("
                        << entry.uncompressed_length << " bytes) to \"" << dstPath
@@ -785,7 +785,7 @@
         return;
     }
 
-    TEMP_FAILURE_RETRY(send(fd, &request, sizeof(request), 0));
+    TEMP_FAILURE_RETRY(send(fd.get(), &request, sizeof(request), 0));
 }
 
 }  // namespace