Unify issue processing and make more robust

The issue processing in gitlog2asciidoc.py missed
certain capitilazation combinations and was split
across 2 ifs.  Combine it into one if and make it case
insensitive using an ugly python(pre 2.7) backwards
compatible method.

Change-Id: I49fb4d66bd5b3777cc9641a947730a19222895f6

tools/gitlog2asciidoc.py

@@ -41,9 +41,19 @@ stdout_value = proc.communicate()[0]
 subject = ""
 message = []
 
+# regex pattern to match following cases such as Bug: 123, Issue Bug: 123, Bug: GERRIT-123,
+# Bug: issue 123, Bug issue: 123, issue: 123, issue: bug 123
+p = re.compile('bug: GERRIT-|bug(:? issue)?:? |issue(:? bug)?:? ',
+               re.IGNORECASE)
+
 for line in stdout_value.splitlines(True):
 
-    if re.match('\* ', line) >= 0:
+    # Move issue number to subject line
+    if p.match(line):
+        line = p.sub('issue ', line).replace('\n',' ')
+        subject = subject[:2] + line + subject[2:]
+
+    elif re.match('\* ', line) >= 0:
         # Write change log for a commit
         if subject != "":
             # Write subject
@@ -61,15 +71,6 @@ for line in stdout_value.splitlines(True):
         subject = line
         continue
 
-    # Move issue number to subject line
-    elif re.match('Bug: ', line) is not None:
-        line = line.replace('Bug: ', '').replace('\n',' ')
-        subject = subject[:2] + line + subject[2:]
-    # Move issue number to subject line
-    elif re.match('Issue: ', line) is not None:
-        line = line.replace('Issue: ', 'issue ').replace('\n',' ')
-        subject = subject[:2] + line + subject[2:]
-
     # Remove commit footers
     elif re.match(r'((\w+-)+\w+:)', line) is not None:
         continue