Description of problem:

root@Dagobah:~# gluster volume quota vol enable / 7GB 
gluster: ../../../cli/src/cli-cmd-parser.c:619: cli_cmd_quota_parse: Assertion `!"opword mismatch"' failed.
Aborted (core dumped)


backtrace of core dumped:
Core was generated by `gluster volume quota vol enable / 7GB'.
Program terminated with signal 6, Aborted.
#0  0x00007fcc8ea963a5 in __GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
64	../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory.
	in ../nptl/sysdeps/unix/sysv/linux/raise.c
(gdb) bt
#0  0x00007fcc8ea963a5 in __GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#1  0x00007fcc8ea99b0b in __GI_abort () at abort.c:92
#2  0x00007fcc8ea8ed4d in __GI___assert_fail (assertion=0x43a2c0 "!\"opword mismatch\"", file=<optimized out>, line=619, 
    function=<optimized out>) at assert.c:81
#3  0x00000000004260ea in cli_cmd_quota_parse (words=0x7fffb113f200, wordcount=6, options=0x7fcc8ca74de0)
    at ../../../cli/src/cli-cmd-parser.c:619
#4  0x000000000040df1b in cli_cmd_quota_cbk (state=0x7fffb113f030, word=0x9b23a0, words=0x7fffb113f200, wordcount=6)
    at ../../../cli/src/cli-cmd-volume.c:1007
#5  0x000000000040a694 in cli_cmd_process (state=0x7fffb113f030, argc=6, argv=0x7fffb113f200) at ../../../cli/src/cli-cmd.c:150
#6  0x000000000040a0ab in cli_batch (d=0x7fffb113f030) at ../../../cli/src/input.c:44
#7  0x00007fcc8ee06efc in start_thread (arg=0x7fcc8ca75700) at pthread_create.c:304
#8  0x00007fcc8eb4189d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#9  0x0000000000000000 in ?? ()
(gdb) f 3
#3  0x00000000004260ea in cli_cmd_quota_parse (words=0x7fffb113f200, wordcount=6, options=0x7fcc8ca74de0)
    at ../../../cli/src/cli-cmd-parser.c:619
619	                GF_ASSERT (!"opword mismatch");
(gdb) l
614	        }
615	
616	        if (strcmp (w, "version") == 0) {
617	                type = GF_QUOTA_OPTION_TYPE_VERSION;
618	        } else {
619	                GF_ASSERT (!"opword mismatch");
620	        }
621	
622	set_type:
623	        ret = dict_set_int32 (dict, "type", type);
(gdb) p w
$1 = 0x43a3c4 "enable"

Wrong usage of the quota cli command should show usage & not line numbers/filenames/assert messages.