Attach Debugger hangs in the "Starting Debugger" dialog when using lldb-mi on OS X.

Reproduce with:
1. Start "/sbin/ping netbeans.org" (other debugees gives similar results)
2. Add the following to end of netbeans.conf (based on "http://wiki.netbeans.org/NewAndNoteworthyNB81"):
### BEGIN
   netbeans_default_options="$netbeans_default_options -J-Dcnd.debugger.lldb=true"
   LLDB_DEBUGSERVER_PATH='/Applications/Xcode_6_2.app/Contents/SharedFrameworks/LLDB.framework/Versions/A/Resources/debugserver'
   export LLDB_DEBUGSERVER_PATH
### END
(note the non-standard Xcode.app location)
3. Start NetBeans, change the GDB debugger path to point at lldb-mi
4. Menu: "Debug->Attach Debugger..."
5. Select the ping process (the "Executable" field is incorrect ("/sbin/ping netbeans.org"), as it includes the command arguments, I do not know whether this is significant)
6. Select OK in the Attach dialog. The "Starting Debugger" progress dialog comes up, and never goes away.
7. Menu: Window->Debugging->Debugger Console
8. The Debugger Console shows:
### BEGIN
This log is saved to: /var/folders/xr/272qfyr13s1cflm4tmq_8ktr0000gn/T/gdb-cmds8664143881699123857.log
NB build: 201503300001
(gdb)
-file-exec-and-symbols "/Users/p/.gdbinit"
(gdb)
MI parse error while parsing 'result list': Expected , or ] but got SYM (/sbin/ping"'.)
(gdb)
### END

So,
a. The -file-exec-and-symbols argument is strange, I think it should have been "/sbin/ping"
b. The "MI parse error" is similar to Bug 217898. 

I can successfully use plain lldb and lldb-mi from the command line. I can successfully use NetBeans with the legacy Apple gdb (6.3.50-20050815).

NetBeans IDE Dev (Build 201503300001), OS X 10.10.2, XCode 6.2, lldb from svn 2015-03-31 (lldb --version says lldb-340.99.0; lldb-mi --version says "... GNU gdb (GDB) 7.4").