Encode string to utf-8 and covert to bytes before sending to pipe

Due to changes in Python3 string handling, strings must be encoded prior to being sent to the pipe, as it may introduce a type error such as:
`TypeError: a bytes-like object is required, not 'str'`

sd-decrypt/decrypt-sd-submission

@@ -17,7 +17,7 @@ def send_progress(msg):
                          "sd-process.Feedback"],
                          close_fds=True,
                          stdin=subprocess.PIPE)
-    p.communicate(msg)
+    p.communicate(bytes(msg.encode('utf-8')))
 
 
 input = sys.argv[1]

sd-journalist/sd-process-download

@@ -68,7 +68,7 @@ wait_for_sigfile(sigfile)
 if os.path.isfile(fn) is False:
     c = subprocess.Popen(["/usr/local/bin/sd-process-feedback"],
                          stdin=subprocess.PIPE)
-    c.communicate('DOWNLOAD_FILE_MISSING\n')
+    c.communicate(bytes("DOWNLOAD_FILE_MISSING\n".encode('utf-8')))
     sys.exit()
 
 fh = tempfile.NamedTemporaryFile(suffix=".sd-xfer", delete=False)
@@ -81,7 +81,7 @@ fh.close()
 # from the same machine? This can only happen on sd-journalist.
 c = subprocess.Popen(["/usr/local/bin/sd-process-feedback"],
                      stdin=subprocess.PIPE)
-c.communicate(input="DOWNLOAD_BUNDLE_CREATED\n")
+c.communicate(bytes("DOWNLOAD_BUNDLE_CREATED\n".encode('utf-8')))
 
 # ship this to the next phase
 subprocess.call(["qvm-open-in-vm", "sd-decrypt", fh.name])

sd-journalist/sd-process-feedback

@@ -5,7 +5,7 @@ import posix
 import sys
 import os
 
-arg = sys.stdin.readline()
+arg = sys.stdin.readline().encode('utf-8')
 
 try:
     fifo = os.open('/home/user/sdfifo', posix.O_WRONLY | posix.O_NONBLOCK)

sd-svs/accept-sd-xfer-extracted

@@ -13,7 +13,7 @@ def send_progress(msg):
                          "sd-process.Feedback"],
                          close_fds=True,
                          stdin=subprocess.PIPE)
-    p.communicate(msg)
+    p.communicate(bytes(msg.encode('utf-8')))
 
 
 send_progress("DECRYPTED_BUNDLE_ON_SVS")