cvsps: cvs log loop uses lookahead to avoid misleading text

Changes cvsps.py's cvs log reader to use a one-line lookahead, so
that possibly misleading log messages can be disambiguated.  In
particular I have past committers who used cvs log's 28-character
row of hyphens within commit messages; this throws cvsps and disrupts
conversion.  The only alternative in this case is to edit the cvs
,v file by hand, which bloodies mercurial's "don't change history"
principle.

hgext/convert/cvsps.py

@@ -191,7 +191,13 b' def createlog(ui, directory=None, root="'
     ui.note(_("running %s\n") % (' '.join(cmd)))
     ui.debug(_("prefix=%r directory=%r root=%r\n") % (prefix, directory, root))
 
-    for line in util.popen(' '.join(cmd)):
+    pfp = util.popen(' '.join(cmd))
+    peek = pfp.readline()
+    while True:
+        line = peek
+        if line == '':
+            break
+        peek = pfp.readline()
         if line.endswith('\n'):
             line = line[:-1]
         #ui.debug('state=%d line=%r\n' % (state, line))
@@ -312,7 +318,7 b' def createlog(ui, directory=None, root="'
                 e.branches = [tuple([int(y) for y in x.strip().split('.')])
                                 for x in m.group(1).split(';')]
                 state = 8
-            elif re_31.match(line):
+            elif re_31.match(line) and re_50.match(peek):
                 state = 5
                 store = True
             elif re_32.match(line):