Update to improved system_properties API.

We'll now return an error if there is an actual error reading the
property, rather than treating it the same as the property not being
set.

Bug: 217728265
Test: mm
Change-Id: I81f22d9ed07443b094f9a64a0737f4d24a2afe15
diff --git a/compos/common/timeouts.rs b/compos/common/timeouts.rs
index c86ae34..e6cc430 100644
--- a/compos/common/timeouts.rs
+++ b/compos/common/timeouts.rs
@@ -35,8 +35,11 @@
 /// Whether the current platform requires extra time for operations inside a VM.
 pub fn need_extra_time() -> Result<bool> {
     // Nested virtualization is slow. Check if we are running on vsoc as a proxy for this.
-    let value = system_properties::read("ro.build.product")?;
-    Ok(value == "vsoc_x86_64" || value == "vsoc_x86")
+    if let Some(value) = system_properties::read("ro.build.product")? {
+        Ok(value == "vsoc_x86_64" || value == "vsoc_x86")
+    } else {
+        Ok(false)
+    }
 }
 
 /// Return the timeouts that are appropriate on the current platform.