Remove at_exit exception handling monkey patch

This is not an issue with newer versions of ruby 1.9.3 and 2.0.0+ as the exit
code does NOT get reset to 0.

Fixes #846

Example code from: https://bugs.ruby-lang.org/issues/5218

```ruby
at_exit do
  raise "X" rescue nil
end

at_exit do
  nil
end

at_exit do
  exit 1
end

at_exit do
  exit 2
end
```

```
$ ruby -v
ruby 2.0.0p576 (2014-09-19) [x86_64-darwin13.4.0]
$ ruby at_exit.rb; echo $?
1
```

```
$ ruby -v
ruby 1.9.3p547 (2014-05-14) [x86_64-darwin13.4.0]
$ ruby at_exit.rb; echo $?
1
```
Fixed a typo on the forms in PXE explorer.

https://bugzilla.redhat.com/show_bug.cgi?id=1158093
https://bugzilla.redhat.com/show_bug.cgi?id=1158205
Fully qualified name for automate was missing leading /

Fixes to the 2 spec and model code to put a leading / for
fqnames
Fix typos in javascript_focus() calls
Merge pull request #949 from mkanoor/automate_fqname_missing_leading_slash

Fully qualified name for automate was missing leading /
Merge pull request #951 from bmclaughlin/fix-broken-javascript-focus-calls

Fix typos in javascript_focus() calls
Merge pull request #943 from jrafanie/remove_spec_helper_kernel_at_exit_patch

Remove at_exit exception handling monkey patch
Allow to save empty display name for an instance

https://bugzilla.redhat.com/show_bug.cgi?id=1148541
Merge pull request #950 from mzazrivec/fix_instance_display_name_edit

Allow to save empty display name for an instance
Delay v2 key generation until first boot

[skip ci]
Merge pull request #955 from jrafanie/generate_v2_key_on_boot

Delay v2 key generation until first boot
Merge pull request #942 from h-kataria/fixed_typo

Fixed a typo on the forms in PXE explorer.