Merge pull request swagger-api#9332 from swagger-api/fix-python-generation-error

fixed out of bound exception for pattern string.

Author: HugoMario

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/FlaskConnexionCodegen.java

@@ -688,8 +688,10 @@ public void postProcessPattern(String pattern, Map<String, Object> vendorExtensi
         if(pattern != null) {
             int i = pattern.lastIndexOf('/');
 
+            //Must follow Perl /pattern/modifiers convention
             if(pattern.charAt(0) != '/' || i < 2) {
-                pattern = String.format("/%s/", pattern);
+                pattern = String.format("/%s/", pattern);;
+                i = pattern.lastIndexOf('/');
             }
 
             String regex = pattern.substring(1, i).replace("'", "\\'");

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java

@@ -265,8 +265,10 @@ public void postProcessPattern(String pattern, Map<String, Object> vendorExtensi
         if(pattern != null) {
             int i = pattern.lastIndexOf('/');
 
+            //Must follow Perl /pattern/modifiers convention
             if(pattern.charAt(0) != '/' || i < 2) {
                 pattern = String.format("/%s/", pattern);
+                i = pattern.lastIndexOf('/');
             }
 
             String regex = pattern.substring(1, i).replace("'", "\\'");