ifcfg-rh/trivial: rename function that are only for testing

We have similar functions, like _nmtst_ip4_config_del_route(). Rename testing
functions to have "_nmtst_" prefix for consistency.

src/settings/plugins/ifcfg-rh/shvar.c

@@ -645,7 +645,7 @@ svFileGetName (const shvarFile *s)
 }
 
 void
-svFileSetName_test_only (shvarFile *s, const char *fileName)
+_nmtst_svFileSetName (shvarFile *s, const char *fileName)
 {
 	/* changing the file name is not supported for regular
 	 * operation. Only allowed to use in tests, othewise,
@@ -655,7 +655,7 @@ svFileSetName_test_only (shvarFile *s, const char *fileName)
 }
 
 void
-svFileSetModified_test_only (shvarFile *s)
+_nmtst_svFileSetModified (shvarFile *s)
 {
 	/* marking a file as modified is only for testing. */
 	s->modified = TRUE;

src/settings/plugins/ifcfg-rh/shvar.h

@@ -35,8 +35,8 @@ typedef struct _shvarFile shvarFile;
 
 const char *svFileGetName (const shvarFile *s);
 
-void svFileSetName_test_only (shvarFile *s, const char *fileName);
-void svFileSetModified_test_only (shvarFile *s);
+void _nmtst_svFileSetName (shvarFile *s, const char *fileName);
+void _nmtst_svFileSetModified (shvarFile *s);
 
 /* Create the file <name>, return a shvarFile (never fails) */
 shvarFile *svCreateFile (const char *name);

src/settings/plugins/ifcfg-rh/tests/test-ifcfg-rh.c

@@ -9156,8 +9156,8 @@ test_write_unknown (gconstpointer test_data)
 
 	sv = _svOpenFile (testfile);
 
-	svFileSetName_test_only (sv, filename_tmp_1);
-	svFileSetModified_test_only (sv);
+	_nmtst_svFileSetName (sv, filename_tmp_1);
+	_nmtst_svFileSetModified (sv);
 
 	if (g_str_has_suffix (testfile, "ifcfg-test-write-unknown-4")) {
 		_svGetValue_check (sv, "NAME", "l4x");