SWS-988 - Fix typo in assertion message

Original pull-request: #67

Author: michalbcz

spring-xml/src/main/java/org/springframework/xml/xsd/commons/CommonsXsdSchemaCollection.java

@@ -134,7 +134,7 @@ public void afterPropertiesSet() throws IOException {
 		Set<XmlSchema> processedImports = new HashSet<XmlSchema>();
 
 		for (Resource xsdResource : xsdResources) {
-			Assert.isTrue(xsdResource.exists(), xsdResource + " does not exit");
+			Assert.isTrue(xsdResource.exists(), xsdResource + " does not exist");
 			try {
 				XmlSchema xmlSchema =
 						schemaCollection.read(SaxUtils.createInputSource(xsdResource));