Clean up C++ client curl configuration (#16064)

(cherry picked from commit 48c575db6fac571acd70bb6568fb067c1d52bf34)
diff --git a/pulsar-client-cpp/lib/auth/AuthOauth2.cc b/pulsar-client-cpp/lib/auth/AuthOauth2.cc
index 33ae450..6cd797e 100644
--- a/pulsar-client-cpp/lib/auth/AuthOauth2.cc
+++ b/pulsar-client-cpp/lib/auth/AuthOauth2.cc
@@ -193,8 +193,6 @@
     curl_easy_setopt(handle, CURLOPT_FORBID_REUSE, 1L);
 
     curl_easy_setopt(handle, CURLOPT_FOLLOWLOCATION, 1L);
-    curl_easy_setopt(handle, CURLOPT_SSL_VERIFYPEER, 0L);
-    curl_easy_setopt(handle, CURLOPT_SSL_VERIFYHOST, 0L);
 
     // Make get call to server
     res = curl_easy_perform(handle);
@@ -260,8 +258,6 @@
     curl_easy_setopt(handle, CURLOPT_FORBID_REUSE, 1L);
 
     curl_easy_setopt(handle, CURLOPT_FOLLOWLOCATION, 1L);
-    curl_easy_setopt(handle, CURLOPT_SSL_VERIFYPEER, 0L);
-    curl_easy_setopt(handle, CURLOPT_SSL_VERIFYHOST, 0L);
 
     // fill in the request data
     boost::property_tree::ptree pt;