Make command-repeat work after gdb.execute

Since commit

  56bcdbea2bed ("Let gdb.execute handle multi-line commands")

command repetition after using the `gdb.execute` Python function
fails (the previous command is not repeated anymore). This happens
because read_command_lines_1 sets dont_repeat, but the call to
prevent_dont_repeat in execute_gdb_command is later.

The fix is to move the call to prevent_dont_repeat to the beginning of
the function.

Tested on my laptop (ArchLinux-x86_64).

gdb/ChangeLog:

	PR python/23714
	* gdb/python/python.c (execute_gdb_command): Call
	prevent_dont_repeat earlier to avoid affecting dont_repeat.

gdb/testuite/ChangeLog:

	PR python/23714
	* gdb.python/python.exp: Test command repetition after
	gdb.execute.
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 1630bd8..d562a4b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2018-11-21  Benno Fünfstück  <benno.fuenfstueck@gmail.com>
+
+	PR python/23714
+	* gdb/python/python.c (execute_gdb_command): Call
+	prevent_dont_repeat earlier to avoid affecting dont_repeat.
+
 2018-11-21  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* Makefile.in (ALL_TARGET_OBS): Add arch/riscv.o.
diff --git a/gdb/python/python.c b/gdb/python/python.c
index a37ed10..d6453e7 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -583,6 +583,8 @@
 
   std::string to_string_res;
 
+  scoped_restore preventer = prevent_dont_repeat ();
+
   TRY
     {
       struct interp *interp;
@@ -612,7 +614,6 @@
 	interp = interp_lookup (current_ui, "console");
 	current_uiout = interp->interp_ui_out ();
 
-	scoped_restore preventer = prevent_dont_repeat ();
 	if (to_string)
 	  to_string_res = execute_control_commands_to_string (lines.get (),
 							      from_tty);
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 093603a..06a1a06 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2018-11-21  Benno Fünfstück  <benno.fuenfstueck@gmail.com>
+
+	PR python/23714
+	* gdb.python/python.exp: Test command repetition after
+	gdb.execute.
+
 2018-11-20  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* gdb.opt/inline-break.exp: Add test that info breakpoint output
diff --git a/gdb/testsuite/gdb.python/python.exp b/gdb/testsuite/gdb.python/python.exp
index 0723507..60423d2 100644
--- a/gdb/testsuite/gdb.python/python.exp
+++ b/gdb/testsuite/gdb.python/python.exp
@@ -121,6 +121,7 @@
 
 gdb_test "python gdb.execute('echo 2\\necho 3\\\\n\\n')" "23" \
     "multi-line execute"
+gdb_test " " "23" "gdb.execute does not affect repeat history"
 
 # Test post_event.
 gdb_py_test_multiple "post event insertion" \