pgsql: Fix up .gitignore and cleanup actions in some src/test/ subdirec

Fix up .gitignore and cleanup actions in some src/test/ subdirectories.

examples/, locale/, and thread/ lacked .gitignore files and were also
not connected up to top-level "make clean" etc.  This had escaped notice
because none of those directories are built in normal scenarios.  Still,
they have working Makefiles, so if someone does a "make" in one of these
directories it would be good if (a) git doesn't bleat about the product
files and (b) cleaning up removes them.

This is a longstanding oversight, but since this behavior is probably
only of interest to developers, there seems no need for back-patching.

Michael Paquier and Tom Lane

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/732b33f8ae4ecc9d7a9f07fd4cb74a60a2a5e2c2

Modified Files
--------------
src/test/Makefile            |    7 ++++---
src/test/examples/.gitignore |    6 ++++++
src/test/examples/Makefile   |    4 ++--
src/test/locale/.gitignore   |    1 +
src/test/locale/Makefile     |    4 ++--
src/test/thread/.gitignore   |    1 +
6 files changed, 16 insertions(+), 7 deletions(-)