Remove unneccessary unsafe code in logger.

Bug: 290018030
Test: m vmbase_example_bin
Change-Id: I0907b641629e3db67080bd8a76f72704ac2c0d65
diff --git a/vmbase/src/logger.rs b/vmbase/src/logger.rs
index c30adad..226d905 100644
--- a/vmbase/src/logger.rs
+++ b/vmbase/src/logger.rs
@@ -25,14 +25,15 @@
 struct Logger {
     is_enabled: AtomicBool,
 }
-static mut LOGGER: Logger = Logger::new();
+
+static LOGGER: Logger = Logger::new();
 
 impl Logger {
     const fn new() -> Self {
         Self { is_enabled: AtomicBool::new(true) }
     }
 
-    fn swap_enabled(&mut self, enabled: bool) -> bool {
+    fn swap_enabled(&self, enabled: bool) -> bool {
         self.is_enabled.swap(enabled, Ordering::Relaxed)
     }
 }
@@ -58,26 +59,19 @@
 
 impl SuppressGuard {
     fn new() -> Self {
-        // Safe because it modifies an atomic.
-        unsafe { Self { old_enabled: LOGGER.swap_enabled(false) } }
+        Self { old_enabled: LOGGER.swap_enabled(false) }
     }
 }
 
 impl Drop for SuppressGuard {
     fn drop(&mut self) {
-        // Safe because it modifies an atomic.
-        unsafe {
-            LOGGER.swap_enabled(self.old_enabled);
-        }
+        LOGGER.swap_enabled(self.old_enabled);
     }
 }
 
 /// Initialize vmbase logger with a given max logging level.
 pub fn init(max_level: LevelFilter) -> Result<(), SetLoggerError> {
-    // Safe because it only sets the global logger.
-    unsafe {
-        log::set_logger(&LOGGER)?;
-    }
+    log::set_logger(&LOGGER)?;
     log::set_max_level(max_level);
     Ok(())
 }