Older versions of tar don't support the --strip-components option so
instead of doing 'tar --strip-components=1 -C source', we now just
untar to the tarball's root directory (pjproject-<version>) and
rename that directory to 'source'.

Also fixed an issue where the pjproject source directory is a hard
coded absolute pathname.

ASTERISK-26510 #close
ASTERISK-22480 #close

Change-Id: I9ec92952507a91ff4e4d01e0149e09fd8e8f32b0