Revert the revert. (its time to sign MR1)

Revert "Waiting till post MR0 - this impacts signing tools for MR0."

This reverts commit a7b5c4a7dc.

Bug: 11334314
Change-Id: I89f8996161e4258b80bf2d0bc7817f0e8e32df13

tools/releasetools/common.py

@@ -954,3 +954,18 @@ def GetTypeAndDevice(mount_point, info):
     return PARTITION_TYPES[fstab[mount_point].fs_type], fstab[mount_point].device
   else:
     return None
+
+
+def ParseCertificate(data):
+  """Parse a PEM-format certificate."""
+  cert = []
+  save = False
+  for line in data.split("\n"):
+    if "--END CERTIFICATE--" in line:
+      break
+    if save:
+      cert.append(line)
+    if "--BEGIN CERTIFICATE--" in line:
+      save = True
+  cert = "".join(cert).decode('base64')
+  return cert