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>

tests/shell/test_shell_interactive.py

@@ -18,6 +18,7 @@
 # specific language governing permissions and limitations
 # under the License.
 
+from __future__ import print_function
 import httplib
 import logging
 import os
@@ -896,14 +897,14 @@ class TestImpalaShellInteractive(ImpalaTestSuite):
       os.chdir("%s/tests/shell/" % os.environ['IMPALA_HOME'])
       result = run_impala_shell_interactive(vector,
         "sOuRcE shell_case_sensitive.cmds; SeLeCt 'second command'")
-      print result.stderr
+      print(result.stderr)
 
       assert "Query: uSe FUNCTIONAL" in result.stderr
       assert "Query: ShOw TABLES" in result.stderr
       assert "alltypes" in result.stdout
       # This is from shell_case_sensitive2.cmds, the result of sourcing a file
       # from a sourced file.
-      print result.stderr
+      print(result.stderr)
       assert "SeLeCt 'second command'" in result.stderr
     finally:
       os.chdir(cwd)