CLEANUP: .gitignore cleanup

.gitignore is an odd beast. All the stuff at the beginning is useless
since in the bottom part starts with /.* and /*. Therefore, the top part
is useless. Moreover, the bottom part makes unignore *.o and
friends. Add it back at the bottom.

.gitignore

@@ -1,51 +1,3 @@
-*.o
-*/.svn
-*~
-.flxdisk*
-.flxpkg
-.flxstatus*
-.svn
-haproxy
-src/*.o
-*.rej
-*.orig
-*.log*
-*.trace*
-haproxy-*
-!doc/haproxy-*.txt
-!src/*.c
-make-*
-dlmalloc.c
-00*.patch
-*.service
-*.bak
-.nfs*
-contrib/base64/base64rev
-contrib/halog/halog
-contrib/ip6range/ip6range
-contrib/iprange/iprange
-tests/test_hashes
-/*.cfg
-/*.conf
-/*.diff
-/*.patch
-/*.c
-/*.o
-/*.so
-/*.txt
-/*.TXT
-/*.txt.*
-/*.prof
-/*.gprof
-/*.prof.*
-/*.gprof.*
-/*.tar
-/*.tar.gz
-/*.tgz
-/*.mbox
-/*.sh
-/bug*
-/TAGS
 # Below we forbid everything and only allow what we know, that's much easier
 # than blocking about 500 different test files and bug report outputs.
 /.*
@@ -69,3 +21,17 @@ tests/test_hashes
 !/src
 !/tests
 !/debian
+# Reject some generic files
+*.o
+*~
+*.rej
+*.orig
+*.bak
+# And reject some specific files
+/contrib/base64/base64rev
+/contrib/halog/halog
+/contrib/ip6range/ip6range
+/contrib/iprange/iprange
+/contrib/systemd/haproxy.service
+/src/dlmalloc.c
+/tests/test_hashes