Install python dependencies early for CH ip.py

When using charmhelpers.contrib.network.ip apt install was quietly
failing. Install python dependencies in the early install hook
(before install.real).

Charm-helpers sync to bring in apt_install with fatal=True

Change-Id: I24ef2178eb57b67e596d3557ab17cafa041ae4c9
Partial-Bug: 1601972

hooks/charmhelpers/contrib/network/ip.py

@@ -414,7 +414,7 @@ def ns_query(address):
     try:
         import dns.resolver
     except ImportError:
-        apt_install('python-dnspython')
+        apt_install('python-dnspython', fatal=True)
         import dns.resolver
 
     if isinstance(address, dns.name.Name):
@@ -458,7 +458,7 @@ def get_hostname(address, fqdn=True):
         try:
             import dns.reversename
         except ImportError:
-            apt_install("python-dnspython")
+            apt_install("python-dnspython", fatal=True)
             import dns.reversename
 
         rev = dns.reversename.from_address(address)

hooks/charmhelpers/contrib/openstack/utils.py

@@ -145,7 +145,7 @@ SWIFT_CODENAMES = OrderedDict([
     ('mitaka',
         ['2.5.0', '2.6.0', '2.7.0']),
     ('newton',
-        ['2.8.0']),
+        ['2.8.0', '2.9.0']),
 ])
 
 # >= Liberty version->codename mapping

hooks/install

@@ -2,7 +2,7 @@
 # Wrapper to deal with newer Ubuntu versions that don't have py2 installed
 # by default.
 
-declare -a DEPS=('apt' 'netaddr' 'netifaces' 'pip' 'yaml')
+declare -a DEPS=('apt' 'netaddr' 'netifaces' 'pip' 'yaml' 'dnspython')
 
 check_and_install() {
     pkg="${1}-${2}"