Fix misspelled Python variable name and typos

Typos:
 - Update pathname in README.txt
 - Fix missing newlines in header update script.

Change-Id: Ib0e053f92a27ff10071b9805fa64e5653ab31b0c

libc/kernel/README.TXT

@@ -56,7 +56,7 @@ the tools you can use are:
 
   * tools/update_all.py
     automatically update all clean headers from the content of 
-    'bionic/kernel/original'. this is the script you're likely going to 
+    'external/kernel-headers/original'. this is the script you're likely going to
     run whenever you update the original headers.
 
 NOTE:

libc/kernel/tools/clean_header.py

@@ -37,7 +37,7 @@ def  cleanupFile( path, original_path):
         src_path = src_path[1:]
 
     if len(src_path) == 0:
-        panic( "oops, internal error, can't extract correct relative path" )
+        panic( "oops, internal error, can't extract correct relative path\n" )
 
     # convert into destination path, extracting architecture if needed
     # and the corresponding list of known static functions

libc/kernel/tools/update_all.py

@@ -37,13 +37,13 @@ if len(optlist) > 0 or len(args) > 1:
 progdir = find_program_dir()
 
 if len(args) == 1:
-    original_dir = arg[0]
+    original_dir = args[0]
     if not os.path.isdir(original_dir):
-        panic( "Not a directory: %s" % original_dir )
+        panic( "Not a directory: %s\n" % original_dir )
 else:
     original_dir = kernel_original_path
     if not os.path.isdir(original_dir):
-        panic( "Missing directory, please specify one through command-line: %s" % original_dir )
+        panic( "Missing directory, please specify one through command-line: %s\n" % original_dir )
 
 # find all source files in 'original'
 #