Telemetry android backend: re-raise BrowserGoneException instead of calling exit() when failing to …

tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py

Index: tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py
diff --git a/tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py b/tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py
index 37874d484c44982d6ded459f255c6e9d27b092ab..d2c13dda6b9447c17279af86fd3d3b9acc4cbc18 100644
--- a/tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py
+++ b/tools/telemetry/telemetry/internal/backends/chrome/android_browser_backend.py
@@ -3,7 +3,6 @@
 # found in the LICENSE file.
 
 import logging
-import sys
 
 from telemetry.core import exceptions
 from telemetry.internal.platform import android_platform_backend as \
@@ -118,10 +117,9 @@ class AndroidBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
             '(1) Flashing to a userdebug build OR '
             '(2) Manually enabling web debugging in Chrome at '
             'Settings > Developer tools > Enable USB Web debugging.')
-        sys.exit(1)
+        self.Close()
+        raise
       except:
-        import traceback
-        traceback.print_exc()
         self.Close()
         raise