[Findit] Remove usage of sys.exit(0) because it still causes exception stack in clusterfuzz.

tools/findit/findit_for_clusterfuzz.py

Index: tools/findit/findit_for_clusterfuzz.py
diff --git a/tools/findit/findit_for_clusterfuzz.py b/tools/findit/findit_for_clusterfuzz.py
index 0365f0ed9b3b22e23272759a07266c6406811586..c101fbcae3610a42ab7cb3a4fe3a38c5f8d8bc9a 100644
--- a/tools/findit/findit_for_clusterfuzz.py
+++ b/tools/findit/findit_for_clusterfuzz.py
@@ -2,8 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import sys
-
 import chromium_deps
 from common import utils
 import crash_utils
@@ -111,19 +109,17 @@ def FindCulpritCLs(stacktrace_string,
       component_to_regression_dict = chromium_deps.GetChromiumComponentRange(
           chrome_regression_start, chrome_regression_end)
       if not component_to_regression_dict:
-        print ('Failed to get component regression ranges for chromium '
-               'regression range %s:%s'
-               % (chrome_regression_start, chrome_regression_end))
-        sys.exit(0)
+        return (('Failed to get component regression ranges for chromium '
+                 'regression range %s:%s'
+                 % (chrome_regression_start, chrome_regression_end)), [])
 
   # Parse crash revision.
   if chrome_crash_revision:
     component_to_crash_revision_dict = chromium_deps.GetChromiumComponents(
         chrome_crash_revision)
     if not component_to_crash_revision_dict:
-      print ('Failed to get component dependencies for chromium revision "%s".'
-             % chrome_crash_revision)
-      sys.exit(0)
+      return (('Failed to get component dependencies for chromium revision "%s"'
+                % chrome_crash_revision), [])
 
   # Check if component regression information is available.
   component_regression = crash_utils.SplitRange(component_regression)