[BUG] Quoted per-cent. sign as literal part of command name

[Ryan Cunningham]

Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-redhat-linux-gnu' 
-DCONF_VENDOR='redhat' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
-DHAVE_CONFIG_H   -I.  -I. -I./include -I./lib  -D_GNU_SOURCE -DRECYCLES_PIDS 
-DDEFAULT_PATH_VALUE='/usr/local/bin:/usr/bin' -D_LARGEFILE_SOURCE 
-D_FILE_OFFSET_BITS=64 -O2 -g -pipe -Wall -Werror=format-security 
-Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong 
--param=ssp-buffer-size=4 -grecord-gcc-switches 
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -m32 -march=i686 -mtune=atom 
-fasynchronous-unwind-tables
uname output: Linux la-escuela-cunningham.org 4.6.4-301.fc24.i686+PAE #1 SMP 
Tue Jul 12 12:09:25 UTC 2016 i686 i686 i386 GNU/Linux
Machine Type: i686-redhat-linux-gnu

Bash Version: 4.3
Patch Level: 42
Release Status: release

Description:
        When BASH finds a per-cent. sign ('%') as the first character of a
        command after quote expansion, such a per-cent. sign is normally
        treated as beginning the identifier of a job to take into the fore-
        ground (or into the background, if the identifier is followed by an
        ampersand ['&']).

        Contrary to current behavior, this should not happen if BASH en-
        counters the per-cent. sign preceded by a backslash ('\') or enclosed
        within quotation marks ("'...'").

        This bug prevents BASH from executing programs whose names begin with
        '%', unless BASH is told not to use the PATH environment variable to
        look for those programs (by the presence of a slash in the first
        argument). This is not an issue in 'zsh':

                [root@la-escuela-cunningham]~# %
                fg: no current job
                [root@la-escuela-cunningham]~# '%'
                zsh: command not found: %

Repeat-By:
        See above.

[This was sent from a computer other than the computer whose copy of BASH had
the bug.]