Add regex -based query

Taking string from bug:
https://bugs.launchpad.net/tripleo/+bug/1926764

Change-Id: Iaf13ca3210e714e4ce859f9cecf8c407ba5e8c2b

output/elastic-recheck/1926764.yaml

@@ -0,0 +1,2 @@
+query: 'message:"Exception: [Errno 2] No such file or directory:"'
+suppress-graph: false

output/sova-pattern-generated.json

@@ -35,6 +35,13 @@
                 "msg": "ReadTimeoutError_HTTPConnectionPool",
                 "pattern": "ReadTimeoutError_HTTPConnectionPool",
                 "tag": "info"
+            },
+            {
+                "id": "missing_file_keepalive",
+                "logstash": "",
+                "msg": "missing_file_keepalive",
+                "pattern": "missing_file_keepalive",
+                "tag": "info"
             }
         ]
     },
@@ -62,6 +69,10 @@
         {
             "name": "ReadTimeoutError_HTTPConnectionPool",
             "regex": "ReadTimeoutError:\\ HTTPConnectionPool"
+        },
+        {
+            "name": "missing_file_keepalive",
+            "regex": "Exception: \\[.+\\] No such file or directory:"
         }
     ]
 }

samples/errors-testing.err

@@ -4,3 +4,4 @@ Killed  timeout -s 9
 Stack overcloud CREATE_FAILED
 java.io.IOException
 curl  http://example.com couldn.t open file "sample/file"
+Exception: [Errno 2] No such file or directory:

src/data/queries.yml

@@ -24,3 +24,7 @@ queries:
     pattern: "ReadTimeoutError: HTTPConnectionPool"
     tags: console
     url: https://bugs.launchpad.net/tripleo/+bug/1449136
+  - id: missing_file_keepalive
+    pattern: "Exception: [Errno 2] No such file or directory:"
+    regex: "Exception: \\[.+\\] No such file or directory:"
+    url: https://bugs.launchpad.net/tripleo/+bug/1926764