releasetools: Replace print stmt with print().

So that it's compatible with Python 3.

Test: pylint --pylint=pylintrc

Change-Id: If06c135a492c94bedd713c8cbdf03155a502d5cd
diff --git a/tools/releasetools/make_recovery_patch.py b/tools/releasetools/make_recovery_patch.py
index 08d1450..7c6007e 100755
--- a/tools/releasetools/make_recovery_patch.py
+++ b/tools/releasetools/make_recovery_patch.py
@@ -14,10 +14,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import print_function
+
 import sys
 
 if sys.hexversion < 0x02070000:
-  print >> sys.stderr, "Python 2.7 or newer is required."
+  print("Python 2.7 or newer is required.", file=sys.stderr)
   sys.exit(1)
 
 import os