[GN] Fix gn_run_binary.py for different error

The debian package builder is throwing a different kind of error.

related dart-lang#31613

Change-Id: I293b31aab310867656ba05b6f62afc8bdc9285e4
Reviewed-on: https://dart-review.googlesource.com/30467
Reviewed-by: Ryan Macnak <[email protected]>
Commit-Queue: Zach Anderson <[email protected]>

Author: zanderso

build/gn_run_binary.py

@@ -26,6 +26,9 @@ def run_command(command):
   except subprocess.CalledProcessError as e:
     return ("Command failed: " + ' '.join(command) + "\n" +
             "output: " + e.output)
+  except OSError as e:
+    return ("Command failed: " + ' '.join(command) + "\n" +
+            "output: " + e.strerror)
 
 def main(argv):
   error_exit = 0