Fixed "format-string" based settings so they can have quotes on them without...

Fixed "format-string" based settings so they can have quotes on them without leaving the quotes in the format string:

(lldb) settings set thread-format "abc"
(lldb) settings set thread-format 'abc'
(lldb) settings set thread-format abc

We strip the quotes before processing the format string and return an "error: mismatched quotes" if mismatched quotes are given.

<rdar://problem/21210789>

llvm-svn: 238896