Fix hard-coded error messages

Signed-off-by: James Bornholt <[email protected]>

mountpoint-s3/tests/cli.rs

@@ -12,7 +12,7 @@ fn mount_point_doesnt_exist() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin("mount-s3")?;
 
     cmd.arg("test-bucket").arg("test/dir");
-    let error_message = "Mount point test/dir does not exist or it is not a directory";
+    let error_message = "mount point test/dir does not exist";
     cmd.assert().failure().stderr(predicate::str::contains(error_message));
 
     Ok(())
@@ -25,7 +25,7 @@ fn mount_point_isnt_dir() -> Result<(), Box<dyn std::error::Error>> {
 
     cmd.arg("test-bucket").arg(file.path());
     let error_message = format!(
-        "Mount point {} does not exist or it is not a directory",
+        "mount point {} does not exist",
         file.path().display()
     );
     cmd.assert().failure().stderr(predicate::str::contains(error_message));