Change default smart connection to ssh on macOS and remove paramiko from requirements.txt (#54738)

* Remove default use of paramiko connection plugin on macOS
    This fix was originally to work around a bug that caused a kernel panic on macOS
    that has since been fixed.
* Remove paramiko from requirements.txt
* Move paramiko checking to common place
* Drop the warnings obfiscation code
* Update pip installation instructions to reflect upstream instructions
* Fix tests on CentOS 6 (Python 2.6) that now show Python deprecation warnings
* Add changelog fragment

lib/ansible/modules/network/panos/_panos_admpwd.py

@@ -81,20 +81,11 @@ ANSIBLE_METADATA = {'metadata_version': '1.1',
                     'status': ['deprecated'],
                     'supported_by': 'community'}
 
-
 from ansible.module_utils.basic import AnsibleModule
+from ansible.module_utils.compat.paramiko import paramiko
 import time
 import sys
 
-HAS_LIB = True
-try:
-    import paramiko
-except ImportError:
-    try:
-        import ansible_paramiko as paramiko
-    except ImportError:
-        HAS_LIB = False
-
 _PROMPTBUFF = 4096
 
 
@@ -189,7 +180,7 @@ def main():
         newpassword=dict(no_log=True, required=True)
     )
     module = AnsibleModule(argument_spec=argument_spec, supports_check_mode=True)
-    if not HAS_LIB:
+    if paramiko is None:
         module.fail_json(msg='paramiko is required for this module')
 
     ip_address = module.params["ip_address"]

lib/ansible/modules/network/panos/_panos_cert_gen_ssh.py

@@ -87,20 +87,11 @@ ANSIBLE_METADATA = {'metadata_version': '1.1',
                     'supported_by': 'community'}
 
 
-from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils._text import to_native
+from ansible.module_utils.basic import AnsibleModule
+from ansible.module_utils.compat.paramiko import paramiko
 import time
 
-HAS_LIB = True
-try:
-    import paramiko
-except ImportError:
-    try:
-        import ansible_paramiko as paramiko
-    except ImportError:
-        HAS_LIB = False
-
-
 _PROMPTBUFF = 4096
 
 
@@ -174,7 +165,7 @@ def main():
     )
     module = AnsibleModule(argument_spec=argument_spec, supports_check_mode=False,
                            required_one_of=[['key_filename', 'password']])
-    if not HAS_LIB:
+    if paramiko is None:
         module.fail_json(msg='paramiko is required for this module')
 
     ip_address = module.params["ip_address"]