[python/Ada] gdb.lookup_type fails to looking primitive type

[python/Ada] gdb.lookup_type fails to looking primitive type

The following change...

    commit 1994afbf19892c9e614a034fbf1a5233e9addce3
    Date:   Tue Dec 23 07:55:39 2014 -0800
    Subject: Look up primitive types as symbols.

... caused the following regression:

    % gdb
    (gdb) set lang ada
    (gdb) python print gdb.lookup_type('character')
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
    gdb.error: No type named character.
    Error while executing Python code.

This is because the language_lookup_primitive_type_as_symbol call
was moved to the la_lookup_symbol_nonlocal hook. A couple of
implementations have been upated accordingly, but the Ada version
has not. This patch fixes this omission.

gdb/ChangeLog:

        * ada-lang.c (ada_lookup_symbol_nonlocal): If name not found
        in static block, then try searching for primitive types.

gdb/testsuite/ChangeLog:

        * gdb.python/py-lookup-type.exp: New file.