Fix popen leak

Related to Bug 637
(cherry picked from commit 540da17300)

tools/linguist/shared/proparser.cpp

@@ -207,6 +207,7 @@ QMap<QString, QString> proFileTagMap( const QString& text )
 		    buff[read_in] = '\0';
 		    after += buff;
 		}
+		pclose( proc );
 		(*it).replace( i, callToSystem.matchedLength(), after );
 		i += after.length();
 	    }