rm useless warning message (#201)

### What problem does this PR solve?

_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._

Issue link:#[[Link the issue
here](https://github.com/infiniflow/ragflow/issues/200)]

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

rag/utils/__init__.py

@@ -37,7 +37,7 @@ def findMaxDt(fnm):
                 if l > m:
                     m = l
     except Exception as e:
-        print("WARNING: can't find " + fnm)
+        pass
     return m
 
   
@@ -55,7 +55,7 @@ def findMaxTm(fnm):
                 if int(l) > m:
                     m = int(l)
     except Exception as e:
-        print("WARNING: can't find " + fnm)
+        pass
     return m