perf_counter tools: remove build generated files

These files are generated during the build process. No need to have
them in the git repository.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Documentation/perf_counter/PERF-BUILD-OPTIONS

-SHELL_PATH='/bin/sh'
-TAR='tar'
-NO_CURL=''
-NO_PERL=''

Documentation/perf_counter/PERF-CFLAGS

--g -O2 -Wall  -DSHA1_HEADER='<openssl/sha.h>' : /home/mingo/bin:libexec/perf-core:share/perf-core/templates:/home/mingo

Documentation/perf_counter/PERF-VERSION-FILE

-PERF_VERSION = 0.0.1.PERF