VCS: Be less strict when matching diff files

The provided regexps can be partial. They must match
from the beginning of the line, but matching line's
end is not required (for example, CVS pattern matches
until first tab)

Change-Id: I8fdf162aebf6d275a9ef1ed3340c0c7599eb36f8
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/vcsbase/vcsbaseeditor.cpp

@@ -831,7 +831,7 @@ void VcsBaseEditorWidget::slotPopulateDiffBrowser()
     for (QTextBlock it = document()->begin(); it != cend; it = it.next(), lineNumber++) {
         const QString text = it.text();
         // Check for a new diff section (not repeating the last filename)
-        if (d->m_diffFilePattern.exactMatch(text)) {
+        if (d->m_diffFilePattern.indexIn(text) == 0) {
             const QString file = fileNameFromDiffSpecification(it);
             if (!file.isEmpty() && lastFileName != file) {
                 lastFileName = file;