IMPALA-11952 (part 2): Fix print function syntax

Python 3 now treats print as a function and requires
the parenthesis in invocation.

print "Hello World!"
is now:
print("Hello World!")

This fixes all locations to use the function
invocation. This is more complicated when the output
is being redirected to a file or when avoiding the
usual newline.

print >> sys.stderr , "Hello World!"
is now:
print("Hello World!", file=sys.stderr)

To support this properly and guarantee equivalent behavior
between python 2 and python 3, all files that use print
now add this import:
from __future__ import print_function

This also fixes random flake8 issues that intersect with
the changes.

Testing:
 - check-python-syntax.sh shows no errors related to print

Change-Id: Ib634958369ad777a41e72d80c8053b74384ac351
Reviewed-on: http://gerrit.cloudera.org:8080/19552
Reviewed-by: Joe McDonnell <joemcdonnell@cloudera.com>
Reviewed-by: Michael Smith <michael.smith@cloudera.com>
Tested-by: Michael Smith <michael.smith@cloudera.com>

bin/generate_xml_config.py

@@ -40,6 +40,7 @@ REPL:
 """
 
 from __future__ import with_statement
+from __future__ import print_function
 import imp
 import os
 import re
@@ -77,7 +78,7 @@ def dump_config(d, source_path, out):
 
       -->
       <configuration>""".format(source_path=os.path.abspath(source_path))
-  print >>out, dedent(header)
+  print(dedent(header), file=out)
   for k, v in sorted(d.iteritems()):
     try:
       k_new = _substitute_env_vars(k)
@@ -87,24 +88,24 @@ def dump_config(d, source_path, out):
     except KeyError as e:
       raise Exception("failed environment variable substitution for value {k}: {e}"
                       .format(k=k, e=e))
-    print >>out, """\
+    print("""\
       <property>
         <name>{name}</name>
         <value>{value}</value>
-      </property>""".format(name=xmlescape(k_new), value=xmlescape(v_new))
-  print >>out, "</configuration>"
+      </property>""".format(name=xmlescape(k_new), value=xmlescape(v_new)), file=out)
+  print("</configuration>", file=out)
 
 
 def main():
   if len(sys.argv) != 3:
-    print >>sys.stderr, "usage: {prog} <template> <out>".format(prog=sys.argv[0])
+    print("usage: {prog} <template> <out>".format(prog=sys.argv[0]), file=sys.stderr)
     sys.exit(1)
 
   _, in_path, out_path = sys.argv
   try:
     mod = imp.load_source('template', in_path)
   except:  # noqa
-    print >>sys.stderr, "Unable to load template: %s" % in_path
+    print("Unable to load template: %s" % in_path, file=sys.stderr)
     raise
   conf = mod.__dict__.get('CONFIG')
   if not isinstance(conf, dict):