[ndk-gdb.py] Improve error message.

Bug: http://b/23787206
Change-Id: I589dac158485cc3605586ec8f9598de8d5d29ba4
diff --git a/ndk-gdb.py b/ndk-gdb.py
index 049dd82..306caea 100755
--- a/ndk-gdb.py
+++ b/ndk-gdb.py
@@ -679,7 +679,7 @@
     retcode,DATA_DIR = adb_var_shell2(['run-as', PACKAGE_NAME, '/system/bin/sh', '-c', 'pwd'])
     if retcode or DATA_DIR == '':
         error('''Could not find package's data directory. Are you sure that
-       your installed application is debuggable?''')
+       the application is installed and debuggable?''')
     log("Found data directory: '%s'" % (DATA_DIR))
 
     # Let's check that 'gdbserver' is properly installed on the device too. If this