Remove SIGAR_INLINE from util functions

There was a problem with compiling sigar on Linux with Clang.
During compilation you got warnings like:

    In file included from linux_sigar.c:30:
    ../../../include/sigar_util.h:80:20: warning: inline function 'sigar_skip_token' is not defined
          [-Wundefined-inline]
    SIGAR_INLINE char *sigar_skip_token(char *p);
                   ^
    linux_sigar.c:137:24: note: used here
                if ((ptr = sigar_skip_token(ptr))) {
                           ^

Which end up in an error like:

    libtool: link: clang -g -O2 -o .libs/cpuinfo cpuinfo.o  ../src/.libs/libsigar.so
    ../src/.libs/libsigar.so: undefined reference to `sigar_skip_token'
    clang: error: linker command failed with exit code 1 (use -v to see invocation)

Removing the non C99 compatible inlining from the functions in include/siger_util.h
solves the problem.

Change-Id: I04bc1d7f5a254e3eda32ca34e000b487db0f6bcd
Reviewed-on: http://review.couchbase.org/39208
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Volker Mische <volker.mische@gmail.com>