Fix byte-compilation warnings in semantic/symref/grep

Fix byte-compilation warnings in semantic/symref/grep

* lisp/cedet/semantic/symref/grep.el (greppattern): Remove.
(grepflags): Rename to semantic-symref-grep-flags.
(semantic-symref-grep-expand-keywords): Update accordingly.
(semantic-symref-grep-use-template): Remove the last two
arguments to make sure they don't shadow the (not renamed)
global variables.
(semantic-symref-perform-search)
(semantic-symref-parse-tool-output-one-line): Use slot names
instead of keywords, like the byte-compiler wants us to.