build: a few ugly hacks to get the rpc tests working out-of-tree

- Link pull-tester/rpc-tests.py to the build dir
- Add the build-dir's config to the python path so that tests can find it
- The tests themselves are in srcdir
- Clean up __pycache__ in 'make clean'

qa/pull-tester/rpc-tests.py

@@ -29,6 +29,7 @@ import subprocess
 import tempfile
 import re
 
+sys.path.append("qa/pull-tester/")
 from tests_config import *
 
 BOLD = ("","")
@@ -37,7 +38,7 @@ if os.name == 'posix':
     # terminal via ANSI escape sequences:
     BOLD = ('\033[0m', '\033[1m')
 
-RPC_TESTS_DIR = BUILDDIR + '/qa/rpc-tests/'
+RPC_TESTS_DIR = SRCDIR + '/qa/rpc-tests/'
 
 #If imported values are not defined then set to zero (or disabled)
 if 'ENABLE_WALLET' not in vars():

qa/pull-tester/tests_config.py.in

@@ -3,6 +3,7 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+SRCDIR="@abs_top_srcdir@"
 BUILDDIR="@abs_top_builddir@"
 EXEEXT="@EXEEXT@"