perf script python: Fix export-to-postgresql.py occasional failure

Occasional export failures were found to be caused by truncating 64-bit
pointers to 32-bits. Fix by explicitly setting types for all ctype
arguments and results.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20180911114504.28516-2-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/scripts/python/export-to-postgresql.py

@@ -204,14 +204,23 @@ from ctypes import *
 libpq = CDLL("libpq.so.5")
 PQconnectdb = libpq.PQconnectdb
 PQconnectdb.restype = c_void_p
+PQconnectdb.argtypes = [ c_char_p ]
 PQfinish = libpq.PQfinish
+PQfinish.argtypes = [ c_void_p ]
 PQstatus = libpq.PQstatus
+PQstatus.restype = c_int
+PQstatus.argtypes = [ c_void_p ]
 PQexec = libpq.PQexec
 PQexec.restype = c_void_p
+PQexec.argtypes = [ c_void_p, c_char_p ]
 PQresultStatus = libpq.PQresultStatus
+PQresultStatus.restype = c_int
+PQresultStatus.argtypes = [ c_void_p ]
 PQputCopyData = libpq.PQputCopyData
+PQputCopyData.restype = c_int
 PQputCopyData.argtypes = [ c_void_p, c_void_p, c_int ]
 PQputCopyEnd = libpq.PQputCopyEnd
+PQputCopyEnd.restype = c_int
 PQputCopyEnd.argtypes = [ c_void_p, c_void_p ]
 
 sys.path.append(os.environ['PERF_EXEC_PATH'] + \