[feature/module_services] Fix check_file_src() function for extensions

tests/functions/fixtures/styles.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<dataset>
+	<table name="phpbb_styles">
+		<column>style_path</column>
+		<column>style_name</column>
+		<column>style_active</column>
+		<column>style_parent_tree</column>
+		<row>
+			<value>subsilver2</value>
+			<value>subsilver2</value>
+			<value>0</value>
+			<value></value>
+		</row>
+		<row>
+			<value>prosilver</value>
+			<value>prosilver</value>
+			<value>1</value>
+			<value></value>
+		</row>
+	</table>
+</dataset>