[docs] Remove experimental tag on Bloom filter predicate

Impala now supports pushing down Bloom filter predicate to Kudu,
by default [1].
Performance testing and associated changes were made to Kudu to reduce
regressions when Bloom filter predicate isn't effective [2].

So removing the experimental tag from the C++ client API docs.

[1] https://issues.apache.org/jira/browse/IMPALA-3741
[2] https://issues.apache.org/jira/browse/KUDU-3140

Change-Id: I1b87ed5b959de70ab587c1e86eb92a7a84091ce9
Reviewed-on: http://gerrit.cloudera.org:8080/16427
Reviewed-by: Attila Bukor <[email protected]>
Reviewed-by: Alexey Serbin <[email protected]>
Tested-by: Bankim Bhavsar <[email protected]>
(cherry picked from commit 0c4f1f9)
Reviewed-on: http://gerrit.cloudera.org:8080/16433
Tested-by: Kudu Jenkins

src/kudu/client/client.h

@@ -1111,17 +1111,9 @@ class KUDU_EXPORT KuduTable : public sp::enable_shared_from_this<KuduTable> {
                                         KuduPredicate::ComparisonOp op,
                                         KuduValue* value);
 
-  /// @name Advanced/Unstable API
-  ///
-  /// There are no guarantees on the stability of this client API.
-  ///
-  ///@{
-
   /// Create a new IN Bloom filter predicate which can be used for scanners on
   /// this table.
   ///
-  /// @warning This method is experimental and may change or disappear in future.
-  ///
   /// A Bloom filter is a space-efficient probabilistic data structure used to
   /// test set membership with a possibility of false positive matches.
   /// See @c KuduBloomFilter for creating Bloom filters.
@@ -1153,6 +1145,11 @@ class KUDU_EXPORT KuduTable : public sp::enable_shared_from_this<KuduTable> {
   KuduPredicate* NewInBloomFilterPredicate(const Slice& col_name,
                                            std::vector<KuduBloomFilter*>* bloom_filters);
 
+  /// @name Advanced/Unstable API
+  ///
+  /// There are no guarantees on the stability of this client API.
+  ///
+  ///@{
   /// Create a new IN Bloom filter predicate using direct BlockBloomFilter
   /// pointers which can be used for scanners on this table.
   ///