Spread around some O_CLOEXEC love.

Also remove some unnecessary SELinux logic when creating image files
for loop devices.

Test: builds, boots, common operations work
Bug: 34903607
Change-Id: I68dfa022ecc39f56c175e786694e0de35b954ca0
diff --git a/Process.cpp b/Process.cpp
index 7dc0144..fd757d5 100644
--- a/Process.cpp
+++ b/Process.cpp
@@ -130,7 +130,7 @@
     char buffer[PATH_MAX + 100];
 
     snprintf(buffer, sizeof(buffer), "/proc/%d/maps", pid);
-    file = fopen(buffer, "r");
+    file = fopen(buffer, "re");
     if (!file)
         return 0;