Eliminates b'' from the revision strings. (#701)

The data parsed from the git output was rteated as a byte array by python.
Doing str() on a byte array gives b'1234567'. By doing decode() on the byte array
we turn it into a string and this liminates the unneeded quotation marks.

bin/revision.py

@@ -103,7 +103,7 @@
 
     # get the short hash
     git_hash = subprocess.check_output(['git', 'rev-parse', '--short', 'HEAD'])
-    git_hash = str(git_hash[:7])
+    git_hash = str(git_hash[:7].decode())
 
     # get the dirty flag
     dirty = os.system('git diff --quiet')